What is the angle between <2,9,-2> <2,9,2> and <0,3,0 ><0,3,0>?

1 Answer
Mar 3, 2017

The angle is =17.4=17.4º

Explanation:

The angle between vecAA and vecBB is given by the dot product definition.

vecA.vecB=∥vecA∥*∥vecB∥costhetaA.B=ABcosθ

Where thetaθ is the angle between vecAA and vecBB

The dot product is

vecA.vecB=〈2,9,-2〉.〈0,3,0 〉 = 27A.B=2,9,2.0,3,0=27

The modulus of vecAA= ∥〈2,9,-2〉∥=sqrt(4+81+4)=sqrt892,9,2=4+81+4=89

The modulus of vecBB= ∥〈0,3,0〉∥=sqrt9=30,3,0=9=3

So,

costheta=(vecA.vecB)/(∥vecA∥*∥vecB∥)=27/(sqrt89*3)=0.95cosθ=A.BAB=27893=0.95

theta=17.4θ=17.4º