Question

Given that the two vectors 8u-v and 4u+3v are perpendicular, and the magnitude of v is 2u , find the angle bet?

Answer 1

Use the fact that \[
\mathbf{a}\cdot \mathbf{b} = ||\mathbf{a}||\cdot ||\mathbf{b} ||\cdot \cos\theta
\]The angle you want is \(\theta\).

Answer 2

Wait a second....

Answer 3

I know that, but they didn't give any number

Answer 4

:[

Answer 5

Use the fact that \[
(8\mathbf{u}-\mathbf{v}) \cdot (4\mathbf{u}+3\mathbf{v}) = 0
\]

Answer 6

8u