Derivative of tanx by first principle

In this video "Derivative or differentiation differentiating of Tan(x) from First Principles Proof" we will prove that the derivative of Tan(x) is Sec^(x) by using first principles. You will also get some practice of taking limits.

In our Previous we also have learnt how we can prove Sinx = Cosx, derivative of a^x=Sec^2X and Cosx= -Sinx by first principle