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First Degree Equations Graphs of 1 st equations Ax + By = C are straight lines.

2.5 conic sections circles-x

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Page 1: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines.

Page 2: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.

Page 3: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

Page 4: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

2x – 3y = 12

Page 5: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

2x – 3y = 12 y = – 4

2 x3

Page 6: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4) 2x – 3y = 12 y = – 4

2 x3

Page 7: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4) 2x – 3y = 12 y = – 4

2 x3

Page 8: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3

Page 9: 2.5 conic sections circles-x

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3 (0,–4)

Page 10: 2.5 conic sections circles-x

Graphs of y = mx + b:

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3 (0,–4)

Page 11: 2.5 conic sections circles-x

Graphs of y = mx + b:

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3

Il. If B = 0, then the equation is of the form x = c whose graph is a vertical line.

12 – 3x = 0

(0,–4)

Page 12: 2.5 conic sections circles-x

Graphs of y = mx + b:

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3

Il. If B = 0, then the equation is of the form x = c whose graph is a vertical line.

12 – 3x = 0 x = 4

(0,–4)

Page 13: 2.5 conic sections circles-x

Graphs of y = mx + b:

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3

Il. If B = 0, then the equation is of the form x = c whose graph is a vertical line.

12 – 3x = 0 x = 4

Graphs of x = c vertical lines:

(0,–4)

(4,0)

Page 14: 2.5 conic sections circles-x

Graphs of y = mx + b:

First Degree EquationsGraphs of 1st equations Ax + By = C are straight lines. There are two cases.I. If B ≠ 0, then solving for y we obtain the format: y = mx + b, when m = slope, and (0, b) in the y-intercept.

(6,0)

(0,–4)

–3y = 12y = –4

2x – 3y = 12 y = – 4

2 x3

Il. If B = 0, then the equation is of the form x = c whose graph is a vertical line.

12 – 3x = 0 x = 4

Graphs of x = c vertical lines:

Graphs of 2nd degree equations: Ax2 + By2 + Cx + Dy = E, (A, B, C, D, and E are numbers) are conic-sections.

(0,–4)

(4,0)

Page 15: 2.5 conic sections circles-x

Conic SectionsOne way to study a solid is to slice it open.

Page 16: 2.5 conic sections circles-x

Conic SectionsOne way to study a solid is to slice it open.

Page 17: 2.5 conic sections circles-x

Conic SectionsOne way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area.

Page 18: 2.5 conic sections circles-x

Conic Sections

A right circular cone

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Page 19: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Page 20: 2.5 conic sections circles-x

Conic Sections

A Horizontal Section

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Page 21: 2.5 conic sections circles-x

Conic Sections

A Horizontal Section

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Circles

Page 22: 2.5 conic sections circles-x

Conic Sections

A Moderately Tilted Section

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Page 23: 2.5 conic sections circles-x

Conic Sections

A Moderately Tilted Section

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Ellipses

Page 24: 2.5 conic sections circles-x

Conic Sections

A Horizontal Section

A Moderately Tilted Section

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Circles and ellipses are enclosed.

Page 25: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

A Parallel–Section

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Page 26: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

A Parallel–Section

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Parabolas

Page 27: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

An Cut–away Section

Page 28: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

An Cut–away Section

Hyperbolas

Page 29: 2.5 conic sections circles-x

Conic Sections

A right circular cone and conic sections (wikipedia “Conic Sections”)

An Cut–away Section

One way to study a solid is to slice it open. The exposed area of the sliced solid is called a cross sectional area. Conic sections are the borders of the cross sectional areas of a right circular cone as shown.

Parabolas and hyperbolas are open.

A Horizontal Section

A Moderately Tilted Section

Circles and ellipses are enclosed.

A Parallel–Section

Page 30: 2.5 conic sections circles-x

Conic Sections

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 31: 2.5 conic sections circles-x

Conic Sections

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections.

Page 32: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 33: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Graphs of Ax2 + By2 + Cx + Dy = E,

Page 34: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Graphs of Ax2 + By2 + Cx + Dy = E,

Page 35: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 36: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

x2 – y2 = 0

For example, the graphs of:

x + y = 0x – y = 0

Page 37: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

x2 – y2 = 0

For example, the graphs of:

x + y = 0x – y = 0

x2 + y2 = 0

(0,0)

(0,0) is the only solution

Page 38: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

x2 – y2 = 0

For example, the graphs of:

x + y = 0x – y = 0

x2 = –1x2 + y2 = 0

(0,0)

(0,0) is the only solution

No solution no graph

Page 39: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.We will match these 2nd degree equations with different conic sections using the algebraic method "completing the square".

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 40: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.We will match these 2nd degree equations with different conic sections using the algebraic method "completing the square". “Completing the Square“ is THE main algebraic algorithmfor handling all 2nd degree formulas.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 41: 2.5 conic sections circles-x

Conic Sections

(Most) Graphs of 2nd equations Ax2 + By2 + Cx + Dy = E,are conic sections. The equations Ax2 + By2 + Cx + Dy = E have conic sections that are parallel to the axes, i.e. not tilted, as graphs. In some special cases their graphs degenerate into lines or points, or nothing.We will match these 2nd degree equations with different conic sections using the algebraic method "completing the square". “Completing the Square“ is THE main algebraic algorithmfor handling all 2nd degree formulas. We need the Distance Formula D = √Δx2 + Δy2 for the geometry.

Circles Ellipses Parabolas Hyperbolas

We summarize the four types of conics sections here.

Page 42: 2.5 conic sections circles-x

CirclesA circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

Page 43: 2.5 conic sections circles-x

CirclesA circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

C

Page 44: 2.5 conic sections circles-x

rr

CirclesA circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

C

Page 45: 2.5 conic sections circles-x

rr

CirclesA circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

C

Page 46: 2.5 conic sections circles-x

rr

The radius and the center completely determine the circle.

CirclesA circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

C

Page 47: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

Let (h, k) be the center of a circle and r be the radius.

(h, k)

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 48: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

(x, y)

Let (h, k) be the center of a circle and r be the radius. Suppose (x, y) is a point on the circle, then the distance between (x, y) and the center is r.

(h, k)

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 49: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

(x, y)

Let (h, k) be the center of a circle and r be the radius. Suppose (x, y) is a point on the circle, then the distance between (x, y) and the center is r. Hence,

(h, k)

r = √ (x – h)2 + (y – k)2

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 50: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

(x, y)

Let (h, k) be the center of a circle and r be the radius. Suppose (x, y) is a point on the circle, then the distance between (x, y) and the center is r. Hence,

(h, k)

r = √ (x – h)2 + (y – k)2

orr2 = (x – h)2 + (y – k)2

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 51: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

(x, y)

Let (h, k) be the center of a circle and r be the radius. Suppose (x, y) is a point on the circle, then the distance between (x, y) and the center is r. Hence,

(h, k)

r = √ (x – h)2 + (y – k)2

orr2 = (x – h)2 + (y – k)2 This is called the standard form of circles.

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 52: 2.5 conic sections circles-x

r

The radius and the center completely determine the circle.

Circles

(x, y)

Let (h, k) be the center of a circle and r be the radius. Suppose (x, y) is a point on the circle, then the distance between (x, y) and the center is r. Hence,

(h, k)

r = √ (x – h)2 + (y – k)2

orr2 = (x – h)2 + (y – k)2 This is called the standard form of circles. Given an equation of this form, we can easily identify the center and the radius.

A circle is the set of all the points that have equal distance r, called the radius, to a fixed point C which is called the center.

rC

Page 53: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

Circles

Page 54: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

must be “ – ”Circles

Page 55: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”Circles

Page 56: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”

(h, k) is the center

Circles

Page 57: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”

(h, k) is the center

Circles

Example B. Write the equation of the circle as shown.

(–1, 3)

Page 58: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”

(h, k) is the center

Circles

Example B. Write the equation of the circle as shown.

The center is (–1, 3) and the radius is 5. (–1, 3)

Page 59: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”

(h, k) is the center

Circles

Example B. Write the equation of the circle as shown.

The center is (–1, 3) and the radius is 5. Hence the equation is:52 = (x – (–1))2 + (y – 3)2

(–1, 3)

Page 60: 2.5 conic sections circles-x

r2 = (x – h)2 + (y – k)2

r is the radius must be “ – ”

(h, k) is the center

Circles

Example B. Write the equation of the circle as shown.

The center is (–1, 3) and the radius is 5. Hence the equation is:52 = (x – (–1))2 + (y – 3)2 or25 = (x + 1)2 + (y – 3 )2

(–1, 3)

Page 61: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Circles

Page 62: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Circles

Page 63: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

Circles

Page 64: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

(3,–2)

Circles

r = 4

Page 65: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

(3,–2)

Circles

r = 4

Page 66: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

(3,–2)

Circles

When equations are not in the standard form, we have to rearrange them into the standard form. We do this by "completing the square".

r = 4

Page 67: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

(3,–2)

Circles

When equations are not in the standard form, we have to rearrange them into the standard form. We do this by "completing the square". To complete the square means to add a number to an expression so the sum is a perfect square.

r = 4

Page 68: 2.5 conic sections circles-x

Example C. Identify the center and the radius of 16 = (x – 3)2 + (y + 2)2. Label the top, bottom, left and right most points. Graph it.

Put 16 = (x – 3)2 + (y + 2)2 into the standard form:

42 = (x – 3)2 + (y – (–2))2

Hence r = 4, center = (3, –2)

(3,–2)

Circles

When equations are not in the standard form, we have to rearrange them into the standard form. We do this by "completing the square". To complete the square means to add a number to an expression so the sum is a perfect square. This procedure is the main technique in dealing with 2nd degree equations.

r = 4

Page 69: 2.5 conic sections circles-x

(Completing the Square)Circles

Page 70: 2.5 conic sections circles-x

(Completing the Square)Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 71: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square,

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 72: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square,

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 73: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square,

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 74: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 75: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2

Page 76: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2

Page 77: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36

Page 78: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

Page 79: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

The following are the steps in putting a 2nd degree equation into the standard form.

Page 80: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

The following are the steps in putting a 2nd degree equation into the standard form.1. Group the x2 and the x–terms together, group the y2 and y terms together, and move the number term the the other side of the equation.

Page 81: 2.5 conic sections circles-x

(Completing the Square)If we are given x2 + bx, then adding (b/2)2 to the expression makes the expression a perfect square, i.e. x2 + bx + (b/2)2 is the perfect square (x + b/2)2.

Circles

Example D. Fill in the blank to make a perfect square.

a. x2 – 6x + (–6/2)2 = x2 – 6x + 9 = (x – 3)2

b. y2 + 12y + (12/2)2 = y2 + 12y + 36 = ( y + 6)2

The following are the steps in putting a 2nd degree equation into the standard form.1. Group the x2 and the x–terms together, group the y2 and y terms together, and move the number term the the other side of the equation. 2. Complete the square for the x–terms and for the y–terms. Make sure add the necessary numbers to both sides.

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Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

Circles

Page 83: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:

Circles

Page 84: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36

Circles

Page 85: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36

Circles

Page 86: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36

Circles

Page 87: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9

Circles

Page 88: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9 ( x – 3 )2 + (y + 6)2 = 32

Circles

Page 89: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9 ( x – 3 )2 + (y + 6)2 = 32 Hence the center is (3 , –6),and radius is 3.

Circles

Page 90: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9 ( x – 3 )2 + (y + 6)2 = 32 Hence the center is (3 , –6),and radius is 3.

Circles

Page 91: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9 ( x – 3 )2 + (y + 6)2 = 32 Hence the center is (3 , –6),and radius is 3.

Circles

Page 92: 2.5 conic sections circles-x

Example E. Use completing the square to find the center and radius of x2 – 6x + y2 + 12y = –36. Find the top, bottom, left and right most points. Graph it.

We use completing the square to put the equation into the standard form:x2 – 6x + + y2 + 12y + = –36 ;complete squares x2 – 6x + 9 + y2 + 12y + 36 = –36 + 9 + 36 ( x – 3 )2 + (y + 6)2 = 9 ( x – 3 )2 + (y + 6)2 = 32 Hence the center is (3 , –6),and radius is 3.

Circles

(3 ,–9)

(3 , –3)

(0 ,–6) (6 ,–6)

Page 93: 2.5 conic sections circles-x

Conic Sections

Page 94: 2.5 conic sections circles-x

Conic Sections

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Conic Sections

Page 96: 2.5 conic sections circles-x

Conic Sections

Page 97: 2.5 conic sections circles-x

Conic Sections

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Conic Sections