100sin(-5пи/4)*cos(-11пи/4)

Question

100sin(-5пи/4)*cos(-11пи/4)

Answer 1

=-100sin5π/4*cos11π/4=-100sin(π+π/4)*cos(3π-π/4)=-100*(-sinπ/4)*cos(π-π/4)=
=100sinπ/4*(-cosπ/4)=-100*√2/2*√2/2)=-100*1/2=-50