Inverse of a weird looking matrix

[LaraCroft]

Homework Statement

If A =

[ -4e^4t sin(9t) -4e^5t cos(9t) ]
[ 4e^4t cos(9t) 4e^5t sin(9t) ]

then what would A^-1 be?

I think I am mainly confused with the cos's and sin's...and all that other junk...since I know how to get the inverse of a regular matrix!

Thank you!

Homework Equations

The Attempt at a Solution

 

[dirk_mec1]

Use the rule of thumb for 2x2-matrix divide the matrix through its determinant change positions of a and d and put a minus sign at b and c.