Find the angle between the two lines whose direction cosines are: and

Question

Philoid · Accepted Answer

Let

R₁ =

And R₂ =

R₁.R₂ = |R₁||R₂|cos

Here, as R1 and R2 are the unit vectors with a direction given by the direction cosines hence, |R1| and |R2| are 1.

So, cos = R₁.R₂ / 1

ð cos

ð =

The angle between the lines is