Question

2cos($frac{pi}{4} -3x)= sqrt{2}$

Answer 1

обе части делим на 2

cos(pi/4-3x)=√2/2

pi/4-3x=arccos(√2/2)=+-pi/4+2pik

-3x=+-pi/4-pi/4+2pik

x1=(pi/4-pi/4+2pik)/(-3)=-2pik/3

x2=(-pi/4-pi/4+2pik)/(-3)=(-pi/2+2pik)/(-3)=pi/6-2pik/3

k-целое