Sum and Difference Formula

$sin(A+B) = sin(A)cos(B) + cos(A)sin(B)$

$cos(A+B) = cos(A)cos(B) – sin(A)sin(B)$

$tan(A+B) = \frac{tan(A) +tan(B)}{1-tan(A)tan(B)}$

Sum to Product

$sin(A) + sin(B) = 2 sin(\frac{A+B}{2}) cos(\frac{A-B}{2})$

$sin(A) – sin(B) = 2 sin(\frac{A-B}{2})cos(\frac{A+B}{2})$

Double Angle Formula

Area of a Triangle

Law of Sines

$\frac{a}{sin(A)} = \frac{b}{sin(B)} = \frac{c}{sin(C)}$