# How do you simplify #tanA - cscA secA (1 - 2cos^2 A)#?

##### 1 Answer

Start by putting all of the terms into sine and cosine. This will make it easier to spot identities and see what might cancel out.

Multiply through the parenthesis..

Now we should find a common denominator. If we multiply the top and bottom of the tangent term by

Combine the numerators.

Now we split the

The Pythagorean theorem states that;

Making this substitution into the numerator we get.

The

The bottom

This is the identity for;