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Apr
21
asked Is there a nice way to interpret this matrix equation that comes up in the context of least squares
Apr
19
accepted Proving that if $f_n \rightarrow f$ uniformly and $f_n$ is integrable then $\int_a^b f_n d\alpha\rightarrow \int_a^b fd\alpha$
Apr
19
comment Proving that if $f_n \rightarrow f$ uniformly and $f_n$ is integrable then $\int_a^b f_n d\alpha\rightarrow \int_a^b fd\alpha$
almost want to delete this question in shame.
Apr
19
comment Proving that if $f_n \rightarrow f$ uniformly and $f_n$ is integrable then $\int_a^b f_n d\alpha\rightarrow \int_a^b fd\alpha$
oh my god......
Apr
19
asked Proving that if $f_n \rightarrow f$ uniformly and $f_n$ is integrable then $\int_a^b f_n d\alpha\rightarrow \int_a^b fd\alpha$
Apr
16
accepted Why do we need $A$ to have linearly independent columns in order for $P_A=A(A^TA)^{-1}A^T$ to hold?
Apr
16
comment Why do we need $A$ to have linearly independent columns in order for $P_A=A(A^TA)^{-1}A^T$ to hold?
@Suugaku No I know, I just don't know why it has to be a basis
Apr
16
asked Why do we need $A$ to have linearly independent columns in order for $P_A=A(A^TA)^{-1}A^T$ to hold?
Apr
5
comment Prove that if $\sum c_n e^{inx}$ converges in $L^2$ to $f$ then $c_n$ are the Fourier coefficients.
I don't see how you got the very first step. How are you able to say that $c_n$ is equal to that? Where, for instance, does the $\frac{1}{2\pi}$ come from?
Apr
5
asked Prove that if $\sum c_n e^{inx}$ converges in $L^2$ to $f$ then $c_n$ are the Fourier coefficients.
Apr
5
comment Prove that the limit of the inner product is equal to the inner product of the limits in $L^2$
Do you know how I can show that that first inequality holds for this norm? I know that any norm satisfies that, but I haven't necessarily proven that this is a norm and I don't have that as a theorem.
Apr
5
revised Prove that the limit of the inner product is equal to the inner product of the limits in $L^2$
changed title
Apr
5
asked Prove that the limit of the inner product is equal to the inner product of the limits in $L^2$
Apr
3
accepted Why is MATLAB giving me these weird eigenvectors?
Apr
3
asked Why is MATLAB giving me these weird eigenvectors?
Apr
2
comment Best Fake Proofs? (A M.SE April Fools Day collection)
@JoeZeng why should there need to be one?
Apr
2
comment Best Fake Proofs? (A M.SE April Fools Day collection)
@LeonardoHerrera "$+$" not "$\times$".
Mar
30
asked Is a broken clock right twice a day?
Mar
27
comment Prove a function has $k$ continuous derivatives from its Fourier series
@Yunfeng I have shown that if $f$ has a $k$-th derivative then $\frac{1}{2\pi}f(x)e^{inx}$ is bounded by $C/|n|^k$. Would that help at all?
Mar
27
comment When does the next bus come?
This is awesome and exactly what I was looking for. Just working through it now. Thanks!