$\lim_{x\to0}\:\frac{ln\left(tan2x\right)}{ln\left(tan3x\right)}$

$\left(xsec\left(\frac{y}{x}\right)-y\right)dx+xdy=0$

$4y^2-8y+3$

$\left(\cos\left(x\right)\right)^2-\left(\sin\left(x\right)\right)^2=\frac{5}{4}$

$-49+16a^2$

$\left(2a^3\cdot a^3\cdot4a\right)^2$

$81z^2+36z+4$