Question

sinx+sin3x
cosy+cos5y

Answer 1

sinx+sin3x=0
2sin2x*cosx=0
sin2x=0
2x=Пn
x=Пn/2, nЭz
cosx=0
x=П/2+Пn, n Эz
2) cosy+cos5y=0
2cos3y*cos2y=0
cos3y=0
3y=П/2+Пn
y=П/6+Пn/3,  nЭz
cos2y=0
2y=П/2+Пn
y=П/4+Пn/2, n z