Question

Cot^2 135-sin210+5cos^2 225

Answer 1

`\cot135^o=\cot(90^o+45^o)=-\tg45^o=-1\\\\\sin210^o=\sin(180^o+30^o)=-\sin30^o=-(1)/(2)\\\\\cos225^o=\cos(180^o+45^o)=-\cos45^o=-(\sqrt2)/(2)`


`\cot^2135^o-\sin210^o+5\cos^2225^o=(-1)^2-\left(-(1)/(2)\right)+5\cdot\left(-(\sqrt2)/(2)\right)^2\\\\=1+(1)/(2)+5\cdot(1)/(2)=1(1)/(2)+2(1)/(2)=4`

Answer: 4.