Why does vector subtraction look like addition?

[Cudi1]

Homework Statement

vector subtraction

Homework Equations

N/A

The Attempt at a Solution

I'm really confused when it comes to subtraction, the following problems seems like an addition problem and i thought it was r+s=t, but i got it wrong. Any help would be gladly appreciated.

 

[ehild]

You can think the subtraction the vector b from a as addition of the opposite of b, (-b) to a: a+b= a+(-b)

ehild

 

[Cudi1]

i think i got it, is it r=s-t?

 

[ehild]

No, r=t-s. If you use the triangle method for addition you see from the figure that r+s=t. So r=t-s.

ehild