cdigital.dgb.uanl.mxcdigital.dgb.uanl.mx/la/1080078053/1080078053_23.pdf · orbit of a planet is...
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cdigital.dgb.uanl.mxcdigital.dgb.uanl.mx/la/1080078053/1080078053_23.pdf · orbit of a planet is not a circle but an ellipse, the sun being in one of the foci, and that the areas