Using the method of differentiation deduce the formula of cos2x starting the formula of tan2x.

Using the method of differentiation deduce the formula of : sin2x starting from the formula of cot2x .

Using the method of differentiation deduce the formula of : cos(x+a) starting from the formula of sin(x+alpha)

Using the method of differentiation deduce the formula of : sin(x+alpha) starting from the formula of cos(x+alpha)

Formula of 2cos^(2)x

Differentiate tan2x+sec2x

Use delta method to find the derivatives of the following : tan2x

From the formula of sin (A + B), deduce the formulae of cos(A + B) and cos (A-B).

Deduce the lens maker's formula.