Just a high schooler who has an interest in math

trying some equations

$2.999999 \approxeq 3$

$\arctan 1=\frac{\pi} 4$

$\cos (\alpha +\beta)= \cos \alpha \cos \beta-\sin \alpha\sin\beta$

$\bigstar$

$\cot \frac{\pi}6 = \sqrt 3$

$\cosh 2 = \frac{e^2+e^{-2}}2$

$m=\frac{\Delta y}{\Delta x} = \frac{y_2-y_1}{x_2-x_1}$

$\Gamma(x) = \int_0^\infty t^{x-1}e^{-t}dt$

$\log_25= \frac{\ln 5}{\ln 2}$

$\lim_{x \to \infty} \bigl(1+\frac 1x\bigr)^x=e$

$\frac{\mathrm d}{\mathrm dx} [5x^3]= 15x^2 \Rightarrow (5x^3)'=15x^2$