# Vectors: Finding the magnitude and direction angle

• Jun 7th 2009, 09:40 AM
Neversh
Vectors: Finding the magnitude and direction angle
I need to find the magnitude and direction angle for the vector A + B given A = <-3,2> and B = <1,4>.

• Jun 7th 2009, 10:25 AM
TheEmptySet
Quote:

Originally Posted by Neversh
I need to find the magnitude and direction angle for the vector A + B given A = <-3,2> and B = <1,4>.

$A+B=<-2,6>$

$||<-2,6>||=\sqrt{(-2)^2+6^2}=\sqrt{4+36}=2\sqrt{10}$

Since the vector is in the 2nd quadrant we get

$\theta=\tan^{-1}\left( \frac{6}{-2}\right)+\pi$