Question

一道很短的数学题求助高手!求过程!高手在哪里!

Answer 1

dz=fx(x,x^2)dx＋fy(x,x^2)dy =﹙x^2-2x^3﹚dx＋fy(x,x^2)dx²

dz＝d﹙x³＋1﹚＝﹙x³＋1﹚′dx=3x²dx

∴2xfy(x,x^2)=3x²－x²＋2x³＝2x³＋2x²

fy(x,x^2)=x²＋x