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2d
comment Can I solve a problem like a combination of PCA and compressed sensing?
and RCA stands for what exactly?
2d
revised How can I prove that this function is continuous in (0,0)?
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2d
comment How can I prove that this function is continuous in (0,0)?
@linofex oops, check now
2d
revised How can I prove that this function is continuous in (0,0)?
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2d
answered How can I prove that this function is continuous in (0,0)?
2d
comment Recursive Equation : $X_t=-\sum_{j=1}^{\infty}\phi^{-j}W_{t+j}$
ah, oops -- I know I had seen something like this before but I've been reading about SDEs where $W_t$ represents a continuous-time Wiener process and forgot that it denotes white noise in autoregression models
2d
revised Recursive Equation : $X_t=-\sum_{j=1}^{\infty}\phi^{-j}W_{t+j}$
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2d
revised Recursive Equation : $X_t=-\sum_{j=1}^{\infty}\phi^{-j}W_{t+j}$
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2d
answered Recursive Equation : $X_t=-\sum_{j=1}^{\infty}\phi^{-j}W_{t+j}$
2d
comment When $a \cdot b$ is minimized and $|a\times b|$ is maximized
@sasha $|b|=|ka|=|k||a|=3|k|$ so $|b|=1$ iff $3|k|=1$
2d
revised Using the extended euclidean algorithm to find Bezout coefficients
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2d
revised Could someone explain a step in this proof please
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2d
comment When $a \cdot b$ is minimized and $|a\times b|$ is maximized
@sasha the Cauchy-Schwarz inequality tells us that $|a\cdot b|$ is maximized when $a,b$ are parallel (i.e. when $b=ka$ for some scalar $k$). So choosing $b$ so that $a\cdot b<0$, then it must be that $a\cdot b$ is a minimum. But note that $k\ne-1$ as $|a|=3$ and so $|b|=1\ne3$
2d
comment Limits in two dimensions
you're not actually approaching in a 'two-dimensional plane' (you're conflating the change of variables with some sort of limit along a path given by the graph of $n\to 1/n$) but instead still allowing $n$ to grow unbounded in a continuous way, only in a qualitatively different way then you might be used to to imagining it
2d
answered Linear algebra: What is the difference between homogenous and particular solutions?
Mar
30
comment Residue theorem application [demonstration]
does it specify what kind of pole? where? is this its sole pole?
Feb
11
comment How to determine linear dependent?
$i+2j-(i+3j)+j=0$ so they're linearly dependent
Feb
3
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Feb
2
comment How does $\arctan\sqrt{f_x^2 + f_y^2}$ result in the slope?
what you have is equivalent to $\tan\phi=|\nabla f|$, but this formula does not encode 'slope' so much as it does a skewed measure of how quickly $f$ varies at some point
Feb
1
revised A level Integration: $\int\frac{x^3}{\sqrt{x^2-1}}dx$
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