## Differentiation of cosx

Here you will learn what is the differentiation of cosx and its proof by using first principle. Let’s begin – Differentiation of cosx The differentiation of cosx with respect to x is -sinx. i.e. $$d\over dx$$ (cosx) = -sinx Proof Using First Principle : Let f(x) = cos x. Then, f(x + h) = cos(x …