# Homework Help: Cosh2x+2sinh^2x, not sure if this goes in this forum

1. May 8, 2010

### pat666

1. The problem statement, all variables and given/known data

Express the function cosh(2x)+2 sinh^2(x)= in terms of exponential functions.

2. Relevant equations

3. The attempt at a solution
i have an answer but im not sure if its right can someone check please.
=1/2 (e^2x+e^(-2x) )+1/2(e^2x-e^(-2x)) if this is right i need some help simplifying.

2. May 8, 2010

### vela

Staff Emeritus
No, it's not right. Check your algebra.

3. May 9, 2010

### pat666

almost certain that the problem is the 2sinh^2(x), i got 1/2(e^x-e^(-x))^2 which my 89 says is right, then i try to simplify to 1/2(e^(2x)-e^-(2x)) which it says is wrong but i cant see why??????????

4. May 9, 2010

### vela

Staff Emeritus
If you're trying to say (a+b)2 = a2+b2, that's the reason why. It's not true. You need to FOIL it out. Also, the 1/2 shouldn't be there because it cancels with the 2 in front.

5. May 9, 2010

### pat666

thanks i agree with one problem you found but i think that the 1/2 should still be there because its squared in sinh^2 (the 2 isnt) giving 1/4 which then becomes 1/2???????????????? not positive though??

6. May 9, 2010

### vela

Staff Emeritus
Oops, you're right. Sorry.