Quadratic Formula: $$ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} $$
Area of a Circle: $$ A = \pi r^2 $$
Derivative of Sine: $$ \frac{d}{dx}(\sin x) = \cos x $$
Bayes' Theorem: $$ P(A|B) = \frac{P(B|A)P(A)}{P(B)} $$
Quadratic Formula:
Derivative of Sine:
[ \mu = \frac{1}{n} \sum_{i=1}^{n} x_i ]
On the same line: ( y = mx + b )