Parallel & Perpendicular Gradients (Edexcel A-Level Mathematics): Flashcards

The product of their gradients is $-1$.

Use $m = (y_2 - y_1) / (x_2 - x_1)$.

Parallel lines have the same gradient.

It is $-1/m$.

Multiply their gradients; result should be $-1$.

Rearrange the equation to isolate $y$ on one side.

The gradient is $3$.

The perpendicular gradient is $-1/2$.

Use negative reciprocal of the original line's slope.

Midpoint = $((x_1+x_2)/2, (y_1+y_2)/2)$.