$\left(a+b\right)^2\:+2\left(a+b\right)\left(c+d\right)\:+\:\left(c+d\right)^2$

$8a^2+4a^3b+6a^3c$

$\frac{12x^6y^2}{18xy^2}$

$a=3,b=4,c=\frac{1}{3},d=\frac{1}{2},m=6,n\frac{1}{4}$

$2\sqrt{2}-4\sqrt{2}+\sqrt{2}$

$\cos\left(\frac{7\pi}{4}-\frac{5\pi}{6}\right)$

$\frac{1-\sin^2x}{\cos x\sin x}=\cot x$