问答题(2020年北京大学

已椭圆 +y2 =1,圆x2 + y2=4,从圆上一点作椭圆的切点弦,求切点弦所围成的面积.

答案解析

如图,设圆上一点(2cost,2sint),对应切点弦方程即为极线方程:xcost+2ysint=1,由于椭圆 x2/a2 + x2/b2 =1在(accost,bsint)处的切线方程为xcos...

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