sin(x/2) + cos(x/2) = ?

Question

anyone knows this?

 

I need it now

Answer 1

You need the half angle formulas.

 

sin(x/2) = sqrt( (1-cos(x) ) /2 )

 

cos(x/2) = sqrt( (1 + cos(x) )/2)

 

There can be a ± in front of the square roots in some situations.