$$\lim_{x\to\frac{\pi}{2}}\left(9cos\left(-3x\right)sec\left(7x\right)\right)$$

$$\left(-m^2+3n^2+4\right)+\left(m^2-n^2\right)$$

$$5x+4y-2x-3xy+x^2$$

$$\frac{1}{4}\left(sin\left(\frac{1}{8}\right)cos\left(\frac{1}{64}\right)+sin\left(\frac{3}{8}\right)cos\left(\frac{9}{64}\right)+sin\left(\frac{5}{8}\right)cos\left(\frac{25}{64}\right)+sin\left(\frac{7}{8}\right)cos\left(\frac{49}{64}\right)\right)$$

$$469\:\:-68\infty$$

$$4^2+3^2$$

$$-3456\cdot396$$