Originally Posted by

**Jeev** Thanks for the tip!

I am now doing some trig identities and would appreciate a quick browse to see if I have made any errors.

I will try to use proper notation to make it easier.

Simplify each trigonometric expression.

a) $\displaystyle \frac{sinx}{tanxcosx}$

$\displaystyle \frac{sinxcosx}{sinxcosx}$

$\displaystyle =1$

b) $\displaystyle sin^4a+sin^2acos^2a$

$\displaystyle =sin^4a+sin^2a(1-sin^2a)$

$\displaystyle =sin^4a+sin^2a-sin^4a$

$\displaystyle =sin^4a-sin^4a+sin^2a$

$\displaystyle =sin^2a$

c) $\displaystyle \frac{sinx-sinxcos^2x}{sin^2x}$

$\displaystyle \frac{sinx-sinx(1-sin^2x)}{sin^2x}$

$\displaystyle \frac{sinx-sinx+sin^2x)}{sin^2x}$

$\displaystyle \frac{sin^2x}{sin^2x}$

$\displaystyle =1$

Sorry if it's still messy, I don't know any of the special commands. I appreciate any help!

EDIT I tried to fix the notation, there is a step missing in part a) but I couldn't figure out how to do a fraction in the denominator.