А) sinx - cosx = 1
Разделим обе части на sqrt(2)
Введём доп.аргумент:
cost = sint = 1/sqrt(2)
sintsinx - costcosx = 1/sqrt(2)
cos(x+t) = -1/sqrt(2)
x+t = ±3π/4 + 2πk,
t = π/4
x = π/2 + 2πn
x = 2πm
б) 2cos^2x - sin(4x) = 1
1 + cos(2x) - 2sin(2x)cos(2x) = 1
cos(2x)(2sin(2x) - 1) = 0
cos(2x) = 0
2x = π/2 + πk
x = π/4 + πk/2
sin(2x) = 1/2
2x = (-1)^n * π/6 + πn
x = (-1)^n * π/12 + πn/2