I'm trying to figure out how to differentiate cos(pi x)/(sin(pi x)+cos(pi x)) and am so confused! Do I combine the chain rule with the quotient rule, and onc I get there how do I simplify? Right now I have an equation that's bigger than the width of the paper.

Thanks for any help!

The derivative of sin(x) (with respect to x) is cos(x)
The derivative of cos(x) (with respect to x) is -sin(x)

You need to combine the chain rule with the quotient rule.