tangent slope which intersect .... 這句話語意不明 (文法也不對, 應該是 intersects)
我猜題意也許是: tangent slope of the curve which is the intersect of the plane x=2 and the surface z=.....
如果題意真是如此, 那麼, 平面和曲面相交的曲線就是:
(把x=2代入z的式中)
在 x=2, y=-1處的切線斜率就是:
(微分後代入y=-1)