Question

Find a ·
b. |a| = 60, |b| = 90, the angle between a and b is 3π/4.

Answer 1

By definition, the dot product between two vectors is given by:

`a.b = | a || b | cos (\alpha)`

We have then that for this case:

`| a | = 60`

`| b | = 90`

`\alpha = (3\pi)/(4)`

Therefore, substituting values we have:

`a.b = | 60 || 90 | cos ((3\pi)/(4))`

`a.b = -3818`

Answer:

The product point of the vectors is:

`a.b = -3818`