2sin4x+√2=0 Cos(x/2-pi/8)=-1

Question

2sin4x+√2=0 Cos(x/2-pi/8)=-1

Answer 1

2sin4x=-V2

sin4x=-V2/2

4x=-pi/4+2pi*k

4x=-3pi/4+2pi*k

x=-pi/16+pi*k/2

x=-3pi/16+pi*k/2

 

cos((x/2)-pi/8)=-1

x/2-pi/8=2pik+pi

x/2=2pi*k+pi+pi/8

x=4pi*k+9pi/4