※ 引述《eric240 (琪^2真的超可愛的)》之銘言：
: Find equations of both the tangent lines to the ellipse
: x^2 + 4y^2 = 36 that pass through the point (12,3)
: 用implicit differentiation求看看..
原式=> 2x+8yy'=0, y'=-x/4y
假設切線通過橢圓上(a,b)
(b-3)/(a-12)=y'=-a/4b
又a=6cosθ
b=3sinθ
代入... 應該解的出來吧
我來試試看@@....
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