Finding resultant vector given two vectors and the angle between them

[danialq15]

Homework Statement

Given two vectors(d and e) in the form of (x,y,z), and given the angle between the vectors, how do you find the resultant vector (a)

Homework Equations

Cosine equation

The Attempt at a Solution

I know that we can use cosine law some how?

 

[genericusrnme]

if the resultant vector is what I think it is (either the vector that goes from the origin to the end of d+e or the vector that goes from the end of d to the end of e) then you don't need to use the law of cosines, you can just add/subtract the vectors d and e from each other

you would have to use the law of cosines of you only have the magnitude of d and e though