# Homework Help: Trig identity

1. Mar 9, 2009

### wes28

1. The problem statement, all variables and given/known data
I am supposed to show that this statement holds true

(csc x + cot x) / (tan x + sin x) = cot x * csc x
using sohcahtoa

2. Relevant equations

3. The attempt at a solution

I have tried this

(( h/o ) + (a/o ) / ( o/a + o/h)) 1st

(( ah / o sqrd )) + ((ah / o sqrd )) 2nd

(ah + ah) / (o sqrd) 3rd

after this I cannot see where to go, to show that it
equals cot x * csc x
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 9, 2009

### praharmitra

do u know how to express all the trigonometric functions in terms of sin and cos???????

If you do, then replace each trig func, with its corresponding sin and cos representation, and simplify both sides separately

Thats one of the ways t do it.

PS - U may also need to use a very important identity concerning sines and cosines

1. $$sin^2(x) + cos^2(x) = 1$$

Can you prove the above identity? (note: that can be done in the method you have already applied to tackle the problem initially)

3. Mar 9, 2009

### praharmitra

do u know how to express all the trigonometric functions in terms of sin and cos???????

If you do, then replace each trig func, with its corresponding sin and cos representation, and simplify both sides separately

Thats one of the ways t do it.

PS - U may also need to use a very important identity concerning sines and cosines

1. $$sin^2(x) + cos^2(x) = 1$$

Can you prove the above identity? (note: that can be done in the method you have already applied to tackle the problem initially)