Question

Tg1⋅ctg1+cos^2(−2π/3)−sin^2 π/4−cos^2 π/4 =

Answer 1

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