Magnitude & Direction (AQA A-Level Mathematics): Flashcards

Length or size of the vector

$\sqrt{a_1^2 + a_2^2}$

$\sqrt{a_1^2 + a_2^2 + a_3^2}$

Angle the vector makes with a reference axis

$\theta = \tan^{-1}\left(\frac{a_2}{a_1}\right)$

Magnitude

$180° + \alpha$ (where $\alpha$ is reference angle)

$l\cos\theta$

$l\sin\theta$

$\sqrt{13}$