Question

given a=3, b=5, and a+b=7, determine a-b

Answer 1

This is a vectors problem, for anyone who would like to help!

Answer 2

Wait, so a and b are lengths of vectors? Because obviously if a=3 and b=5 then a+b=8 not 7...

Answer 3

they are the lengths of vectors, yes.

Answer 4

\[|a|=3, |b|=5, and |a+b|=7, determine |a-b|\] is what i meant to put there.

Answer 5

It's usually a good idea to draw out a picture and label it with the vectors a, b, a+b, and a-b and see if you can figure it out from there.

Answer 6

If not though, you can use the law of cosine to find out some important information as well.

Answer 7

is a+b my c value then? because i know cosine law is a^2 + b^2 - 2ab cos c