Question

Sin^2 t-cos^2 t , если t= П/3

Answer 1

$sin^2 t-cos^2 t=-(cos^2 t-sin^2 t)=-cos2 t= \\\ =-cos \frac{2 \pi }{3} =-(- \frac{1 }{2}) = \frac{1 }{2}=0,5$