Question

sin(x+п/4)+sin(x-п/4)<1

Answer 1

sinx*cosп/4+sinп/4*cosx+sinx*cosп/4-sinп/4*cosx<1
2sinx*cosп/4<1
√2sinx<1
sinx<1/√2
3п/4+2пn<x<п/4+2пn