Вычислите: 3cos(7π/2 + α)+2sin(17π - α), если sinα= -0.2

Question

Вычислите:
3cos(7π/2 + α)+2sin(17π - α), если sinα= -0.2

Answer 1

3cos(7π/2 +α) +2sin(17π -α) =3cos(2π +3π/2 +α) +2sin(2*8π +π -α) =
3cos(3π/2 +α) +2sin(π -α) = 3sinα+2sinα =5sinα =||sinα= -0,2|| = 5*(-0,2)  = -1.