Question

Given a=i+j, b=i-j, and u=2i+3j, express u in terms of a and b. [Hint: let u=ma+nb]

Answer 1

Let u=ma+nb
2i+3j=m(i+j)+n(i-j)
=mi+mj+ni-nj
=(m+n)i+(m-n)j
Nw let us compare the coefficients of i and j
m+n=2-(1)
m-n=3-(2)
(1)+(2)=>
m+n+m-n=2+3
2m=5
From this m can be found. then plug in that value in either (1) or (2) and find n.

Answer 2

Alright thankyou so much!

Answer 3

welcome:)

Answer 4

wait i dont understand the part where you did m+n=2-(1) where did u get the 1

Answer 5

I just name the equation as (1)

Answer 6

oh okay

Answer 7

ohh i get it. Thankss :)

Answer 8

Welcome:)