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visits member for 2 years, 7 months
seen Jul 25 at 20:18

Mar
19
comment How do i prove that the reduced row echelon form is unique?
You only defined the property of being in reduced row echelon form. This is a yes/no question. I cannot think of a natural definition for uniqueness from your question.
Mar
19
comment to show $X$ is disconnected
You don't need a concept of a "mother space" to define connectedness - it's all about finding two open subsets $A,B\subset X$ with $A\cap B=\emptyset$ and $A\cup B=X$.
Mar
19
comment $g:\mathbb{C}\rightarrow\mathbb{C}$ be analytic and $g(0)\neq 0$ we need to calculate $\frac{1}{2\pi i}\int_{|z|=r>0} f(z)g(z) dz$
Calculate residue at 0 using Laurent series?
Mar
17
answered 7th class question my daughter asked and need answer if possible
Mar
10
comment Show that $f(z)$ has no antiderivative in $\,S=\mathbb{C}\setminus \{-i,i\}$
@mrf: Then i think it would be more correct to say "You could've also picked an integral around z=-i, because you'd get similar problems", instead of just "repeat". "Repeat" makes it sounds like they're both necessary.
Mar
10
comment Show that $f(z)$ has no antiderivative in $\,S=\mathbb{C}\setminus \{-i,i\}$
In the third solution, the repetition for $z=-i$ is not necessary - you have already proven that the antiderivative does not exist in the given area.
Mar
10
comment Show $I=\{sf\mid s\in \mathbb Z_{11}[x]\}$ matches $J=\{h \in \mathbb Z_{11}[x] \mid h(1) = h(-2) = 0\}$.
@haunted85: Those are just the roots of $f$.
Mar
10
revised Show $I=\{sf\mid s\in \mathbb Z_{11}[x]\}$ matches $J=\{h \in \mathbb Z_{11}[x] \mid h(1) = h(-2) = 0\}$.
added 14 characters in body
Mar
10
comment Show $I=\{sf\mid s\in \mathbb Z_{11}[x]\}$ matches $J=\{h \in \mathbb Z_{11}[x] \mid h(1) = h(-2) = 0\}$.
$f(\overline 2)=\overline 4$ so $f\not\in J$ but $f\in I$ with $s=1$. So $I\neq J$
Mar
10
answered Show $I=\{sf\mid s\in \mathbb Z_{11}[x]\}$ matches $J=\{h \in \mathbb Z_{11}[x] \mid h(1) = h(-2) = 0\}$.
Mar
10
comment Show $I=\{sf\mid s\in \mathbb Z_{11}[x]\}$ matches $J=\{h \in \mathbb Z_{11}[x] \mid h(1) = h(-2) = 0\}$.
In the definition of $I$, don't you mean $s\in\mathbb{Z}_{11}[x]$?
Feb
9
comment What is inverse of $I+A$?
By substituting $A'=A-I$, you are basically asking for the inverse of all matrices.
Feb
6
comment Example of an increasing, integrable function $f:[0,1]\to\mathbb{R}$ which is discontinuous at all rationals?
@Belgi: that depends on your measure...
Jan
31
comment A box contains 150 oranges.If one orange is taken…
@AndréNicolas: I read it as a "factory of boxes" question, in which some process generates uniformly distributed rotten oranges. If you know the probability for this exact box, then apparently you have already counted the rotten ones.
Jan
31
comment A box contains 150 oranges.If one orange is taken…
Strictly speaking, we don't know the number of good oranges. There could be 150 bad oranges in the box. We can only give the estimated number of good oranges.
Jan
30
comment Algorithm to find the numbers expressible as the sum of two positive cubes in two different ways
Of course, in Haskell, you wouldn't need to stop anywhere. You can just calculate them all and print a finite subset.
Jan
21
comment Filter signal through convolution
@Kristian: Oh, then perhaps you haven't reached this yet, but convolution in the time domain is multiplication in the Fourier domain. So just take the Fourier transform of both, multiply, and detransform.
Jan
21
comment Filter signal through convolution
Why don't you use fourier analysis? You correctly tagged it as such.
Jan
20
comment Solution of integration of $e^{x^2}$
@MårtenW: I must admit I missed that, but of course this can be solved by some appropriate complex substitution.
Jan
20
comment Solution of integration of $e^{x^2}$
By "elementary", we mean "elementary functions", such as taking powers and multiplying and addition. There is no expression for the integral $e^{x^2}$. We can only give it a name (specfically the "error function"). I don't know how one can prove this.