296 reputation
213
bio website stonehead.net
location Oslo, Norway
age 25
visits member for 2 years, 11 months
seen Nov 15 '13 at 19:25

Student of music, math and sound recording.

@jodles89


Aug
15
comment A basic doubt on linear dependence of vectors
I think you mean "since t is not in the subspace spanned by u, v and w."
Dec
7
comment Why is $\mathbf{\hat{x}} = \sum_{j=2}^n (\mathbf{x}\cdot\mathbf{u}_j)\mathbf{u}_j = \mathbf{x} - (\mathbf{x}\cdot \mathbf{u})\mathbf{u}$?
Thanks, David! That's what I needed! Weird how it's so obvious after someone told you where to look...
Oct
20
comment Different results for row reduction in Matlab
@J.M. I am using MATLAB 7.11.0 (R2010b).
Oct
20
comment Different results for row reduction in Matlab
@J.M. and Agusti, I think I might have narrowed it down to a rounding error, causing the top and bottom row to be slightly different (but not shown due to lack of decimals shown in Matlab). As you are both more experienced here than me, do you think I should answer my own post or delete it? Thank you!
Oct
10
comment Showing that $\{ 1, \cos t, \cos^2 t, \dots, \cos^6 t \}$ is a linearly independent set
Thank you for your answer, Arturo! I think my problem might stem from a misunderstanding of what linear independence requires. I thought for functions to be linearly independent, they need to be so for all $\mathbb{R}$; however, it seems like it's the other way around: i.e. if a set of functions are not linearly dependent for all $\mathbb{R}$, then they are linearly independent. So if we can show one example of linear independence, then we're done. Is that the gist of what you were saying?
Oct
10
comment Showing that $\{ 1, \cos t, \cos^2 t, \dots, \cos^6 t \}$ is a linearly independent set
Thank you for your answer, André! Forgive me for asking, but it is not obvious to me why the fact that $\cos t$ can take on more than 6 different values makes a contradiction?
Oct
8
comment Showing that a one-to-one linear transformation maps a linearly independent set onto a linearly independent set
Thank you for the counterexample!
Sep
4
comment Showing that $\mathbf{u}=\mathbf{0}$ for $c\mathbf{u}=\mathbf{0}$, $c$ nonzero
Good point, thanks!
Sep
4
comment Showing that $\mathbf{u}=\mathbf{0}$ for $c\mathbf{u}=\mathbf{0}$, $c$ nonzero
@Srivatsan: Good to know, thanks!
Sep
4
comment Showing that $\mathbf{u}=\mathbf{0}$ for $c\mathbf{u}=\mathbf{0}$, $c$ nonzero
@Chandrasekhar: Thanks!
Sep
1
comment editing signal in frequency domain and converting back to time domain
You might want to post this at StackOverflow as well, for more answers (or even avp.stackexchange.com under signal-processing).
Sep
1
comment Prove that there are an infinite number of primes that start with the number $n$ in a base $b$ system
Sorry, I did not mean to distort the meaning; I just rewrote it in LaTeX according to the parentheses in the original post.
Aug
31
comment Meaning of, and how to verify, a vector space *over* $\mathbb{R}$
+1 Thank you for the detailed explanation, Michael!
Aug
31
comment Meaning of, and how to verify, a vector space *over* $\mathbb{R}$
@D B Lim: I put good advice into action!:)
Aug
31
comment Meaning of, and how to verify, a vector space *over* $\mathbb{R}$
@Willie: Thank you, that explained it! I suggest you consider writing that textbook! gary: I have not seen or learnt about fields or finite fields yet. I'll keep an eye out for that though!
Aug
31
comment Help with the proof of the characterization of linearly dependent sets
@D B Lim: Thank you D B Lim! You're right, Lay has given me the impression that linear algebra is mostly about matrices... I'll pick the book up at my library right away! Thank you for the helpful suggestion!
Aug
31
comment Help with the proof of the characterization of linearly dependent sets
Thanks D B Lim! +1! Vector spaces are the next chapter in the book, so I'll have a go at these once I've had a look in that chapter.
Aug
30
comment Help with the proof of the characterization of linearly dependent sets
@D B Lim: Thank you! That makes perfect sense!
Aug
30
comment Help with the proof of the characterization of linearly dependent sets
Thank you! I think I got it! Now the point with the second part, where v_1 is not zero, is that then not all numbers c_2 -> c_p can be zero (for it to be linearly dependent), which in turn leads to the fact that v_j is a linear combination of the preceding vectors... Have I kind of got it? I have at least got what I initially asked for, so I'm marking your post as the answer:)
Aug
30
comment Help with the proof of the characterization of linearly dependent sets
Sorry, I didn't mean to rephrase it. Do you mean that we're simply saying that v_1 is a trivial linear combination in this case; and that it could just as fine be a non-trivial combination as well (but for the sake of the proof we're assuming the former)?