## Archive for the ‘vectors’ Category

## Problem 764

What are the projection of the point (-2,3,10)on the coordinate planes?

On the x y – plane: ( __,__ ,__)

On the y z – plane: (__, __ ,__ )

On the x z- plane : (__ ,__ ,__)

**Solution:-**

On the x y – plane: (-2,3,0)

On the y z – plane: (0,0,10)

On the x z- plane : (-2,0,10)

## Problem 653

Find the appropriate angle between the vectors.

u = (3, -5, 2), and (-9, 5, 1)

**Solution:-**

To find the angle we use the identity

=

## Problem 652

Compute the dot product of the vectors u and v.

u = (3, -5, 2), and (-9, 5, 1)

**Solution:-**

u .v = u_{1}v_{1} + u_{2}v_{2} + u_{3}v_{3}

Therefore u .v = (3)*(-9)+(-5)(5)+(2)(1)

= -27 – 25 + 2

= -50.