$\lim_{x\to\frac{3.14}{2}}5cos\left(5x\right)sec\left(9x\right)$

$2\:\cos\:\left(\frac{\theta}{2}\right)=1$

$x+3\le-1$

$\sin\left(x\right)\left(\tan\left(x\right)\right)=1+\cos\left(x\right)$

$40a^3+0.5-22a^3+4.12$

$4x^2-9<0$

$2cosx\:-\:sinx\:=\:\frac{3}{\left(2cosx+sinx\right)}$