5 sin 11п/12 cos 11п/12

Question

5 sin 11п/12 cos 11п/12

Answer 1

2sinx*cosx=sin2x

Следовательно отсюда

2.5*2sin11π/12*cos11π/12=2.5*sin2*11π/12=

=2.5*sin11π/6= -2.5*sin(10π/6+π/6)=-2.5*sin π/6=

= -2.5 * 1/2= -1.25