Question

Professor said I don't need to use the definition of the derivative for these questions. How should I solve?
1) f(x)= (2-x)/(1+x)
2) f(x)= x sinx

Answer 1

Solve for what?

Answer 2

Find f'(x) from first principles

Answer 3

Wait, axiomatically?! Unless you're proving the definition of derivative... Actually, I don't even know what it means to find the derivative without using a derivative. If you mean by logical arguments... I think I *may* understand you, apart from that...