Hello everyone,

Could someone please explain this problem to me? This is correct, but I don't understand it.

z=f(x,y), x=x(u,v), y=y(u,v) and x(1,2/0=5, y(1,2)=3

Calculate zu(1,2) in terms of some of the numbers a,b,c,d,e,k,p,q, where
fx(1,2)=a, fy(1,2)=c, xu(1,2)=e, yu(1,2)=p, fx(5,3)=b, fy(5,3)=d, xv(1,2)=k, yv(1,2)=q

Use the chain rule:

zu(u,v)=fx(x,y)xu(u,v)+fy(x,y)yu(u,v)

since x(1,2)=5 and y(1,2)=3, substituting zu(1,2)=fx(5,3)xu(1,2)+fy(5,3)yu(1,2)=

be+dp

Thank you very much