- #1
Petkovsky
- 62
- 0
The vectors are in 3D space:
1. It says:
|Q| = 2 and |P| = 3. Angle between the vectors is 30. Find a = P - 2Q.
-- So for this one, i used the angle formula cos (alpha) = (Q*P) / (|Q| * |P|)
and got QP = 3sqrt(3). However i don't know how to proceed from this point on.
2. |a - b| = 22, |a| = 13 ,| b| = 19. Find |a+b|
With this one i honestly don't know how to start.
Edit:
Ok, i drew quadrilateral, with a and b being the sides, and a+b and a-b the diagonals. I think that i might solve it.
1. It says:
|Q| = 2 and |P| = 3. Angle between the vectors is 30. Find a = P - 2Q.
-- So for this one, i used the angle formula cos (alpha) = (Q*P) / (|Q| * |P|)
and got QP = 3sqrt(3). However i don't know how to proceed from this point on.
2. |a - b| = 22, |a| = 13 ,| b| = 19. Find |a+b|
With this one i honestly don't know how to start.
Edit:
Ok, i drew quadrilateral, with a and b being the sides, and a+b and a-b the diagonals. I think that i might solve it.