Revision sheet · Mathematics

Straight lines

Slope from two points: $m = \frac{y _{2} - y _{1}}{x _{2} - x _{1}}$
Slope from the angle with the x-axis: $m = tan θ$
Slope of a perpendicular line: $m_{2} = - \frac{1}{m _{1}}$
Point-slope form of a line: $y = y_{1} + m (x - x_{1})$
Two-point form of a line: $y = y_{1} + \frac{y _{2} - y _{1}}{x _{2} - x _{1}} (x - x_{1})$
Intercept form of a line: $y = b (1 - \frac{x}{a})$
Distance from a point to a line: $d = \frac{∣ A x _{1} + B y _{1} + C ∣}{A ^{2} + B ^{2}}$
Distance between two parallel lines: $d = \frac{∣ C _{1} - C _{2} ∣}{A ^{2} + B ^{2}}$