# Thread: Can anyone help with a linear alg problem

1. ## Can anyone help with a linear alg problem

The problem is in the attachment. (a matrix involve trigonometry). I wonder if anybody can help!

yybn

2. Look at the case where $\theta _1 = 0\;\& \,\theta _2 = \frac{\pi }{2}$

3. ## Thanks Plato

Thanks! Plato

This sounds a very good idea to start. But could you give me a more general proof? ( the formula to be used are:
sin(X+Y)= sin (X)cos(Y)+cos(X)sin (Y)
cos(X+Y)=cos(X)cos(Y)-sin(X)sin(Y)

Thanks a lot!

yybn