Question

If →u and →v are the vectors below, find the vector →w whose tail is at the point halfway from the tip of →v to the tip of →v−→u and whose head is at the point halfway from the tip of →u to the tip of →u+→v. Assume all vectors are in standard position.

→u = −4,−2,3 →v = −1,−1,−2 [→w = −11/2,−7/2,−3 <--- my answer]


The correct answer is:

→w = −11/2, −5/2, 11/2

I don't know what I am doing wrong..

Answer 1

I get the answer you are supposed to get. Details follow.

Answer 2

Tip of V = -1 , -1 , -2
Tip V-U = +3 , +1 , -5
halfway V to V-U is average
= (3-1)/2 , 0/2 , (-2-5)/2 = +1 , 0 , -7/2

Tip of U = -4 , -2 , +3
Tip V+U= -5 , -3 , +1
halfsum = -9/2 , -5/2 , 2
now finish
-9/2 - 1 = -11/2
-5/2 - 0 = -5/2
2 - - 7/2 = 11/2

Answer 3

Oh I see now, thank you so much!

Answer 4

You are welcome.