# Math Help - Using first principles, find the derivative of y = tanx.

## Using first principles, find the derivative of y = tanx.

I am rather terrible at using trigonometric proofs, which is needed in doing this question.

Question is title of this thread.

My attempt:

Originally Posted by**Kakariki**

I am rather terrible at using trigonometric proofs, which is needed in doing this question.

I don't know what to do from here. I need to show all my steps to get the answer. I know the answer is , but don't know how to show it using first principles.

If you could show me what to do next, I would be very grateful.

Use this identity:

So

Thus, Source: mathhelpforum.comCategory: Bank

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