# Question on linear dependence: Where do I go wrong?

Printable View

• November 19th 2011, 02:08 AM
Lotte1990
Question on linear dependence: Where do I go wrong?
Hello,

I tried to find a solution (see attachment) to the exercise in the attachment, but somehow I end up with two values for k that do not result in linear dependent vectors. Where do I go wrong? What SHOULD I do? And what are the right values for k?

Please help! (Worried)
• November 19th 2011, 02:35 AM
Deveno
Re: Question on linear dependence: Where do I go wrong?
you dropped a minus sign in the third row in the second column.

what you should have ended up with, in the 3,3 position is:

$1 - \frac{4}{k} + \frac{3}{k} - \frac{2}{k^2}$

some additional comments:

1) please make an effort to type your questions out. many people will not address problems that are entirely from images.
2) since you divide by k several times in the course of the row-reduction, you should check before-hand that 0 is not a value that makes the set linearly dependent.
3) rather than use the substitution x = 1/k, just get your expression over a common denominator. since this equals 0, you can just consider the numerator, and will not have to substitute back for k when you're done.
• November 19th 2011, 03:51 AM
Lotte1990
Re: Question on linear dependence: Where do I go wrong?
You are right! Thanks!