Question

Sen(180+x) + cos(90+x) + senx + cos(270+x)

Answer 1

sen180 = -x
x = - sen180
x = 0
cos90 = -x
x = -cos90
x= 0
sen x = 0
cos270= -x
x = -cos270
x = 0
x*x*x*x = 0