Homework Statement
Given this formula
Sum
sin(a+b)=sin(a)*cos(b)+cos(a)*sin(b)
prove this one
Difference
sin(a-b)=sin(a)*cos(b)-cos(a)*sin(b)
Given this formula
Sum
cos(a+b)=cos(a)*cos(b)-sin(a)*sin(b)
prove this one
Difference
cos(a-b)=cos(a)*cos(b)+sin(a)*sin(b)...