[sage-support] Simplify trig and sin(0.500000000000000*pi)

Hello, I have a term t that I simplify with t.simplify_trig(). Parts of the result look something like this: 65*sin(0.500*pi)*sin(x2)*cos(x3)*sin(x5)+... My limited math understanding tells me that sin(0.5*pi) is zero, therefore the term shouldn't be there. Is there a way to let sage

[sage-support] Simplify matrix with variables

Hello there, I have a little kinematic project running. I have a matrix with Denavit-Hartenberg parameters for each joint. See http://upload.wikimedia.org/math/6/e/3/6e3a9d7ad118c01e0e8b06cdc6d0205f.png In my case everything except theta is constant. I need to multiply this matrix with itself for