Question

cos(2x+pi/4)=0

sin(x+3pi/4)=0

Answer 1

1. 2x+п/4=п/2+Пk
2x=п/4+Пk
x=п/8+Пk/2
2.
sin(x+П/2+п/4)=0
cos(x+п/4)=0
x=П/4+Пk
k∈Z

Answer 2

cos(2x+π/4)=0;
cos(π/2)=0;
2x+π/4=π/2;
2x=π/2-π/4;
2x=π/4;
x=π/8.
sin(x+3π/4)=0;
sin(0)=0;
x+3π/4=0;
x=-3π/4.