Question

Proof?
sinx+cosx=√2 sin(x+pi/4)

Answer 1

We will use trigonometric addition formulas on the right side of an equation:
`√(2) (sinx*cos ( \pi )/(4) +cosx*sin ( \pi )/(4))= =√(2)(sin x* ( √(2) )/(2) + cosx * ( √(2) )/(2)=`=sinx + cos x.
Equation is true.