- #1

- 120

- 0

## Homework Statement

Let f(x,y)=[itex]e^{xy}[/itex]

Variables u and v are defined by u=[itex]x^{3}[/itex]-[itex]y^{3}[/itex] , v=[itex]x^{2}+xy[/itex]

Find the values of [itex]\delta[/itex]f/[itex]\delta[/itex]u and [itex]\delta[/itex]f/[itex]\delta[/itex]v at the point where x=-1 and y=2

## Homework Equations

N/A

## The Attempt at a Solution

At first I thought that I'd have to write x and y in terms of u and v. So, I started by factorising using the difference of two cubes for u and then just taking out a factor of x for v. However, I pretty much hit a brick wall there.

And, if I can't write x and y in terms of u and v, I can't see how I could find either [itex]\delta[/itex]f/[itex]\delta[/itex]u or [itex]\delta[/itex]f/[itex]\delta[/itex]v?