Upload
scott-cobb
View
212
Download
0
Embed Size (px)
Citation preview
9.9 The Fundamental
Theorem of Algebra
The Fundamental Theorem of Algebra
• Every polynomial equation with complex coefficients and positive degree n has exactly n complex roots.
• You may have to count the same number more than once if it is a root.
double
• Theorem: If a polynomial equation with real coefficients has as a root (a and b real), then is also a root. In other words, imaginary roots come in pairs -
.
• Just like we did with quadratic equations, we can also write the equation of any polynomial from its roots.
a +bi a−bi
complex conjugates
Find the polynomial equation of least degree having the given roots.
1. 2, 1, -4
Find the polynomial equation of least degree having the given roots.
2. 2, 1, 1+ i
Given the following root(s) for the polynomial equation, find
the remaining roots.
3. x3 −3x2 + x−3 =0; 3
Given the following root(s) for the polynomial equation, find
the remaining roots.
4. x3 −2x2 −4x−16 =0; −1+ i 3
Given the following root(s) for the polynomial equation, find
the remaining roots.
5. x4 +11x2 +18 =0; −3i
Given the following root(s) for the polynomial equation, find
the remaining roots.
6. x4 + 4x3 + 2x2 −12x−15 =0; −2 −i