$5x^4+\frac{3}{2}x^2-\frac{1}{2}x^4$

$-12x^2+3x+1<0$

$\lim_{x\to\infty}\left(\frac{v-1-\sqrt{v^2-7}}{v-4}\right)$

$4x^2+5x+4=0$

$r=\frac{2\cos70}{\sin20}+\cos\left(30\right)+sec\left(30\right)$

$\lim_{x\to\infty}\left(cos\frac{12\pi}{11^x}\right)$

$\lim_{n\to\infty}\:1+\left(-21\right)^{2n}$