(3-4sinx)·(3+4cosx)=0
3-4sinx = 0
4sinx = 3
sinx = 0,75
х = (-1)^k arcsin(0.75) + πk k∈Z
3+4cosx = 0
4cosx = -3
cosx = -0.75
x = ±(π - arccos 0.75) + 2πk k∈Z