Question

calcule sen 7pi/2 - sen 17pi/2+sen (-pi/2)

Answer 1

7π/2 = 4π/2 + 3π/2 = 2π + 3π/2

17π/2 = 16π/2 + π/2 = 8π + π/2

sen7π/2 - sen17π/2 + sen(-π/2) = sen3π/2 - senπ/2 + sen(-π/2) =

= -1 - (+1 ) + (-1) = -1 - 1 - 1 = -3