# How can I find angle θ between two vectors?

## There are two I'm stuck on 1) u = <3, 2> v = <4, 0> I definitely struggle with these types of problems so if there's any pointers for remembering formulas etc that'd be greatly appreciated :)

Feb 22, 2018

vecu.vecv = |vecu||vecv|cos θ

This is the Formula for Dot product of two vectors; can also be used to find the angle between these vectors.

#### Explanation:

:. cos θ = (vecu.vecv)/(|vecu||vecv|)

rArr θ = cos^(-1)[(vecu.vecv)/(|vecu||vecv|)]

rArr θ = cos^(-1){ (<3, 2>.<4, 0>)/((3^2+2^2)^(1/2).(4^2+0^2)^(1/2))}

rArr θ = cos^(-1){12/(4.(13)^(1/2))}

:.θ = cos^(-1){3/(13)^(1/2)} rArrθ = 0.588°

NOTE = To remember the formula, write it again and again on your rough notebook and Yes do a lot of questions based on that formula. Practice and hardwork is the only key to success.............................................😊😊😊