Question

tg1⋅ctg1+cos^2(−2π/3)−sin^2 π/4−cos^2 π/4 =

Answer 1

$tg1*Ctg1+Cos^{2}(-frac{2pi }{3})-Sin^{2}frac{pi }{4}-Cos^{2}frac{pi }{4}=1+(-frac{1}{2})^{2}-(Sin^{2}frac{pi }{4}+Cos^{2}frac{pi }{4})=1+frac{1}{4}-1=frac{1}{4}=0,25$