Question

Vector a = 3i + (-2)j
Vector b = -5i + 6j

What is the magnitude of a + b?

What is the direction of a + b in radians?

Answer 1

I got the magnitude as 4.5. How do I get the direction?

Answer 2

Ok so you agree that you have a two-dimensional vector right? A vector can be broken into it's components, x and y.

Think of it as a triangle. All you need to to is to an arctangent(y component/x component)

Answer 3

keep in mind that your angle should be in quadrant 2

Answer 4

So I do tan^-1(4/-2)?

Answer 5

Yes, but you need to "fix" the angle so that it is in quadrant 2, assuming your answer isn't already there