Unknown008
Nov 14, 2010, 10:58 PM
1. Combine the two fractions on the left hand side.
2. Use the difference of two squares; (a+b)(a-b) = a^2 - b^2, on the denominator.
3. Expand the numerator.
4. Simplify.
You should get there fast enough.
ebaines
Nov 15, 2010, 02:08 PM
Hint: first step is to replace the cotu and tanu functions with their sine and cosine equivalents.