Don't forget the chain rule with these.
The last one.
The best way to do these is the way earboth showed.
Take the partials with respect to x and y:
Same as above. See?.
1. sin(x+y) = x-y The answer is (1-cos(x+y))/((cos x+y)+1)
I believe this is when i went wrong or something.
2. cos(xy)=1-x^2 the answer is (2x-y sin (xy))/(x sin (xy))
And I got lost from here.
3.ln(xy)=e^2x The answer is (2e^2x-x^-1)y
And then this step was when I got lost as to how this translates to the answer.