Question

Please help with this pre calc problem! Let v1= (-6,4) and v2=(-3,6).

With these values find:

-The angle between v1 and v2

-The scalar projection of v1 onto v2

-The projection of v1 onto v2

Answer 1

for the angle between v1 and v2, would I find the distance between the points to figure out all the sides?

Answer 2

just find dot product to find the angle.

Answer 3

v1 dot v2 = ||v1|| * ||v2|| * cos(x)
where x is the angle between them

Answer 4

Oh! Wow, that makes more sense. And how about the scalar projection and regular projection?

Answer 5

there are easy formulas, just google them

Answer 6

the math editor is messed up, so it would look like a mess

Answer 7

Thanks for the tips!

Answer 8

@zzr0ck3r I got 27 for the angle. Is that right?

Answer 9

And is this the right equation for scalar projection? b∙a/||a||

Answer 10

http://www.wolframalpha.com/input/?i=cos^%28-1%29%2842%2F%28sqrt%2836%2B16%29sqrt%2845%29%29%29%3D+