$\left|15\right|-\left|-9\right|$

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

$4\cdot18$

$x^2+0.0625+4x^4$

$\lim_{w\to0}\left(\frac{w^2}{1-cos\left(w\right)}\right)$

$\lim_{x\to\infty}\left(\frac{\pi}{2}-\arctan\left(x\right)\right)$

$\lim_{x\to3}\left(\frac{x^2-9}{x^2+5x-6}\right)$