題目 4. (10 points) Evaluate ∂u∂y∣(2,0)\left.\dfrac{\partial u}{\partial y}\right|_{(2,0)}∂y∂u(2,0) for u(x,y)=h(x2+y2,3x−4y)u(x,y)=h(x^2+y^2, 3x-4y)u(x,y)=h(x2+y2,3x−4y) where h(s,t)=t4s−t2+tanslns.h(s,t)=\frac{t}{4s}-t^2+\frac{\tan s}{\ln s}.h(s,t)=4st−t2+lnstans. 解答
