3sin23pi/4*cos23pi/4=?

Question

3sin23pi/4*cos23pi/4=?

Answer 1

3sin23π/4*cos23π/4 =3/2* 2sin23π/4*cos23π/4 =3/2*sin2*23π/4=
3/2*sin23π/2=3/2*sin(6*2π -π/2) = 3/2* (-sinπ/2) = 3/2* (-1) = -1,5.