$$16y^2+40xy+400$$

$$\frac{\cot\left(a\right)\tan\left(a\right)-\sin^2\left(a\right)}{\sin\left(a\right)\cot\left(a\right)}$$

$$y'=5x^{-\frac{3}{4}},\:y\left(1\right)=4$$

$$u\left(x\right)=\ln\left(x^3+7x\right)$$

$$verify\:\frac{tanx}{cosxcscx}=sec^2x-1$$

$$\lim_{x\to\infty}\left(\frac{2^x-\:x}{\ln\left(x^2\right)}\right)$$

$$-4.5-\left(-2.1\right)$$