$\frac{dp}{dt}+2tp=-p+4t-2$

$\lim_{x\to\infty}\left(\frac{ln\left(8x+9\right)}{ln\left(7x+5\right)+2}\right)$

$8.3\sin\left(18\right)$

$\lim_{x\to\frac{x}{6}}\frac{\tan x}{\sin^2x}$

$\left(-3+\frac{3k}{n}\right)^2$

$29\cdot20$

$cos\left(a+b\right)=cosacosb-sinasinb$