Ecuaciones clave - Precálculo

Ley de senos	$\begin{array}{l} \frac{sen α}{a} = \frac{sen β}{b} = \frac{sen γ}{c} \\ \frac{a}{sen α} = \frac{b}{sen β} = \frac{c}{sen γ} \end{array}$
Área para triángulos oblicuos	$\begin{array}{r} Área = \frac{1}{2} b c sen α \\ = \frac{1}{2} a c sen β \\ = \frac{1}{2} a b sen γ \end{array}$

Ley de cosenos	$\begin{array}{l} a^{2} = b^{2} + c^{2} - 2 b c \cos α \\ b^{2} = a^{2} + c^{2} - 2 a c \cos β \\ c^{2} = a^{2} + b^{2} - 2 a b c o s γ \end{array}$
fórmula de Herón	$\begin{array}{l} Área = \sqrt{s (s - a) (s - b) (s - c)} \\ donde s = \frac{(a + b + c)}{2} \end{array}$

Fórmulas de conversión

\begin{array}{l} \cos θ = \frac{x}{r} \to x = r \cos θ \\ sen θ = \frac{y}{r} \to y = r sen θ \\ r^{2} = x^{2} + y^{2} \\ \tan θ = \frac{y}{x} \end{array}