error with cosinus
When I type "cos(8pi/7)", Sage answers me cos(1/7pi)
wich is wrong. I exchanged with some people who had the correct answer "-cos(1/7*pi)". So I guess the problem is with my CPU or my configuration. But how to change that ? Thanks
In what version of SageMath are you observing that error?
This is the oldest version i have on some older machine, works well: