Posted by Cameron on Thursday, April 26, 2012 at 9:32am.
r(v-w)=(r+s)i-20j
start with the i componnets.
r(v-w) dot i=r+s
(5ri-2rj-ri-3rj)dot i= r+s
5r-r=r+s
4r=s
Now the j components
r(v-w)dot j=-20
-2r-3r=-20
r=4 then s=1
check my work, please
WAT DO U MEAN BY DOT?
The answer given above is incorrrect
let v = [5,-2) and w = [1,3]
then v-w = [4,-5]
so we want r[4,-5] = [r+s, -20]
then 4r = r+s and -5r = -20
3r = s and r = 4
then r = 4, then s = 12
verification:
LS = r(v-w)
= 4[4,-5] = [16, -20]
RS = [r+s, -20 = 16, -20 ] = LS
My answer is correct!