Question

Find the derivative of y=sin(x+y).

Answer 1

I don't know. It's a multiple choice question and I got cos(x+y) as the answer but it's wrong.

Answer 2

Then how should I do this?

Answer 3

if you're taking the derivative with respect to x, you have to remember to chain rule the y.

Answer 4

So the answer must be cos(x+y)/(1-cos(x+y)), right?