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visits member for 2 years, 11 months
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8m
comment Boundary value problem and eigenvalues for strum-liouville
What you tried? How far have you got? I hope my fellow users won't rush to answer before you share some of your own work.
14m
answered Is the set of complex solutions to $x^2+y^2 = 1$ isomorphic to $\mathbb{C}^*$?
1h
comment Example of a continuous function such that f(X)=Y.
$[0,1]$ and $[2,3]$ look like disjoint intervals to me. Hmm ...
1h
comment Help with limits of 2 variables
This procedure of using power series expansions is usually 'illegal' in intro courses.
1h
reviewed Approve suggested edit on Example of a continuous function such that f(X)=Y.
1h
comment Example of a continuous function such that f(X)=Y.
What have you tried? Looks like there is an obvious candidate function or two.
1h
revised Lognormal Random Variable
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1h
comment Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
Turns out they are the same. As $2n - 1 = n + (n -1)$, then $${2n - 1 \choose n} = {2n - 1 \choose n - 1}$$
1h
comment Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
As $2n - 1 = n + (n -1)$, then $${2n - 1 \choose n} = {2n - 1 \choose n - 1}$$
2h
revised Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
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2h
comment Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
Because if you first choose the committee from everyone there are indeed ${2n \choose n}$ possible committees. But now you have no idea how many of those came from the Presidential eligible group. There are not necessarily $n$ committee members eligible to be President; it could be any number from $0$ to $n$.
2h
revised Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
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2h
revised Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
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2h
answered Prove $\sum_{k=0}^n k{n\choose k}^2 = {n{2n-1\choose n-1}}$
2h
comment Defective wires - probability
Thanks for adding the examples.
3h
reviewed Approve suggested edit on Devriative of $\frac {1} {\sqrt{x+1}}$ using first principle
3h
revised Showing Convergence of Sequence using Cauchy Sequence
edited body
3h
reviewed Approve suggested edit on Showing Convergence of Sequence using Cauchy Sequence
3h
comment Prove this inequality $ \sqrt{5} > \frac {13 + 4\pi}{24 - 4\pi} $
What have you tried? What techniques are permitted here?
3h
answered Showing Convergence of Sequence using Cauchy Sequence