**1. Why do we need to differentiate trigonometric functions?**

One reason is that sometimes there is a need to find the gradient of a trigonometric graph.

**2. Do I need to be able to prove all of the derivatives of the six basic trig functions from first principles?**

There is probably no need to be able to prove them but you should certainly be able to follow and understand these proofs.

**3. Do I need to memorise the derivatives of the six basic trigonometric functions?**

You should try an memorise them even though they are provided in the

Formulae and Tables Bookletprovided with the Bursary examination paper.