$\frac{\left(sin\:2x\right)}{\:sin\:\left(\left(\frac{\pi\:}{2}\right)-\:x\right)}\:=\:2sin\left(x\right)$

$cos\:=-\frac{4}{5}$

$\sec\left(2\right)x\cot\left(2\right)x=\csc\left(2\right)x$

$x^4+x^3-23x^2+31x^3+6x$

$\left(x-y\right)^2=x^2-2xy+y^2$

$210-756m^2+882m^4-343m^6$

$\:8x^3+\:2^2\:-27x\:-18$