$\lim_{x\to0}\left(\frac{\left(e^{\frac{-1}{x}}\right)}{x}\right)$

$\frac{d^2}{d^2x}\left(\left(x-1\right)^2-\left(y-3\right)^2=4\right)$

$\lim\:_{u\to\:\:0}\left(\cos\:\left(u\right)\left(1+\frac{\sin\:\left(2u\right)}{\cos\:\left(2u\right)}\right)^{\frac{u}{2}}\right)$

$-102x\left(4\right)$

$\log_{4}\left(x+3\right)=2$

$\frac{\sin^2-2\sin x+1}{2\sin x+1}$

$7y-8-7y-4$