[persian54]

Originally Posted by Wes.

You've taught? As a TA?

Anyway:

∂u(x1,x2)/∂x1 = (x1x2 +6.8)^53 + 11

then repeat for x2 (i.e., ∂u(x1,x2)/∂x2)

(I've just forgotten a lot of the rules. Finding partials is no problem, but when it's disguised like the example that I gave, I don't remember how to start).

Quoted from a friend:

so these are pretty simple
you basically are taking the derivative with respect to one variable
for instance, in the firs one, youre taking the derivative with respect to x1
which means you treat x2 as a constant
for instance if you had 5x1x2
your deriv would be 5x2
or if you had (5x1x2)^3

it woud be 250x2^3 x1^2
but basically youre treating these as the same as single variable derivatives
just pretending the other variable is a constant