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Aug
27
comment Factor $x^5 + x + 1$
I have no idea what the $2x-x$ is supposed to do for you. But you can get some mileage out of adding and subtracting $x^2$, that is, writing $(x^5-x^2)+(x^2+x+1)$.
Aug
27
comment Finding $P$ Such that $D=P^TH\overline P$
What do $L^{-*}$ and $L^{-T}$ mean?
Aug
27
comment Find the coefficients($x^{15}$,$x^{11}$) of the function $(2x^2-\frac{3}{x})^{10}$
OP labeled it "homework", and asked for "advice how to continue". OP will not now have the pleasure of working out the solution.
Aug
27
revised Calculate the sum of the following series
typo in title
Aug
27
comment Calculate the sum of the following series
Hint: The Binomial Theorem.
Aug
27
comment Find the coefficients($x^{15}$,$x^{11}$) of the function $(2x^2-\frac{3}{x})^{10}$
If that's what you call a hint, what do you call a complete answer?
Aug
27
comment $a,b,c>0,a+b+c=21$ prove that $a+\sqrt{ab} +\sqrt[3]{abc} \leq 28$
Equality, by the way, is obtained when $a=16$, $b=4$, $c=1$.
Aug
27
comment $a,b,c>0,a+b+c=21$ prove that $a+\sqrt{ab} +\sqrt[3]{abc} \leq 28$
Source of the problem, please?
Aug
27
awarded  Enlightened
Aug
27
comment Why some functions are not integrable?
No, Banach-Tarski only comes up in higher dimensions, non-integrability already comes up in one dimension.
Aug
27
comment Why some functions are not integrable?
It's not easy to explain this without invoking some high-powered stuff. One can find a non-measureable subset of the interval $[0,1]$. Then the function that is 1 on that set and zero elsewhere won't be integrable.
Aug
27
revised Would the answer of the square root of a square root be positive or negative?
typos
Aug
27
awarded  Nice Answer
Aug
27
answered $1^k+2^k+\cdots+n^k\mod n$ where $n=p^a$.
Aug
27
answered How can we prove that the sum of all elements of $A^{\displaystyle-1}$ is $5$?
Aug
27
revised How can we prove that the sum of all elements of $A^{\displaystyle-1}$ is $5$?
typo in title
Aug
27
comment A question regarding a step in power method justification (Writing a vector in terms of the eigenvectors of a matrix)
"the proof of the power method" Which proof? In which book/paper/website/t-shirt?
Aug
27
comment Solution to Linear Nonhomogeneous Differential Equation
If you want to get someone's attention, you have to put @ before the name.
Aug
27
comment Calculating all minimal generators of a finite group
Note, by the way, that if $p$ is a large prime, then there is no known efficient way to find even one minimal generating set of the multiplicative group modulo $p$, even though it's known that the group is cyclic.
Aug
27
comment Calculating all minimal generators of a finite group
Of course there is a way to calculate all minimal generating sets of a given finite group; test every subset of the group to see whether it is a generating set, starting with the 1-element subsets, then the 2-element subsets, etc. You might want to refine the question.