2sin(3π/4)*cos(3π/4)

Question

2sin(3π/4)*cos(3π/4)

Answer 1

2sin(3π/4)*cos(3π/4)=2*корень2/2*(-корень2/2)=-1

Answer 2

2sin(3pi/4) *cos(3pi/4)  =  sin(2* 3pi/4)  =  sin3pi/2  =  -1

Использовали  формулу     sin2a  =  2sina * coosa

 

Ответ.   -1