Question

E=sen x -cos 2 x + cos 3x sen 3x - cos x para x= 90°

Answer 1

E = senx - cos2x + cos3x.sen3x - cosx

E = sen90 - cos180 + cos270.sen270 - cos90

E = 1 - (-1) + cos(180+90).sen(180+90) - 0

E = 1+1 + (cos180.cos90 - sen180.sen90).(sen180.cos90+sen90.cos180)

E = 2 + (-1.0 - 0.1).(0.0+1.(-1))

E = 2+ 0.(-1)

E = 2