# Linear Math Inverse

1. Oct 17, 2009

### ~Sam~

1. The problem statement, all variables and given/known data
pt)
If A=
4e^4t x sin(4t) 4e^2t x cos(4t)
-3e^4t x cos(4t) 3e^2t x sin(4t)

Then A inverse is?

x= times
^=power

sorry for bad format

2. Relevant equations

Since it's 2x2 I know you can use the determinant equation 1/(ad-bc) ..etc

3. The attempt at a solution

Because of the weird variables I'm not sure how to simplify the multiplication when doing the determination equation.

2. Oct 17, 2009

### Hurkyl

Staff Emeritus
I assume you've have managed to get an answer that is correct, and are just looking for help simplifying?

Care to show us what you got? (Or, maybe just the expression you got for the determinant?)

3. Oct 17, 2009

### ~Sam~

well the answer i got was long..i just subbed the variables in the equation.

4. Oct 18, 2009

### HallsofIvy

Staff Emeritus
?? You "subbed the variables" into what equation?

5. Oct 18, 2009

### willem2

use $$sin^2(t) +cos^2(t) = 1$$