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visits member for 2 years, 6 months
seen 8 hours ago

8h
comment hard question, please help
See codegolf.stackexchange.com/questions/4019/…
9h
comment If we know $a^{1 / 2} + a^{-1/2}$, how can we calculate $a + a^{-1}$?
@PauloCosta, Use the formula, set $x=a^{1/2},y=a^{-1/2}$
9h
comment Series with $n$th term having integer raised to the power of $n$ in the denominator
It's incorrect, we don't need it particularly though if you follow the linked answers.
9h
comment Series with $n$th term having integer raised to the power of $n$ in the denominator
The $n$th term $$=\frac{4\cdot5\cdot6\cdots(n+3)}{6\cdot9\cdot12\cdots(3n+3)},$$ right?
9h
comment Series with $n$th term having integer raised to the power of $n$ in the denominator
See math.stackexchange.com/questions/746388/…
12h
comment Find all intergers such that $2n^2+1$ divides $n^3+9n-17$
@Ewin, Welcome. We still need to test for $2\le n\le8$. I'm thinking of reducing that like $n\not\equiv\pm2\pmod5$ as $153\not\equiv0\pmod5$
18h
comment Angle in a triangle within a circle.
@ZubinMukerjee, I left it for Blakes7
19h
comment Ellipse focal proof
@whyguy, How about this?
1d
comment Can this be rewritten as the following?
$$x(x^2-1)-1(x-1)=x(x-1)(x+1)-1(x-1)=(x-1)[x(x+1)-1]=\cdots$$
1d
comment Computing $ \lim_{x \to 0} \left( \frac {1}{x} - \frac {1}{\sin x } \right) $
Can we use mathworld.wolfram.com/SeriesExpansion.html ?
1d
comment What does “versin” mean?
en.wikipedia.org/wiki/Versine
1d
comment Neat Diophantine Equation Question
@math110, Factorize $\dfrac{a^n}4=p\cdot q$ where $(p,q)=1$
1d
comment Prove $\lim_{x \to 0} \frac{e^{\sin(x)} - e^{\tan (x)}}{e^{\sin (2x)}-e^{\tan (2x)}} = \frac{1}{8}$
@Nick, how about this?
1d
comment Evaluation of a finite sum
Resembles math.stackexchange.com/questions/591350/…
1d
comment finding root of 3rd degree math equation
en.wikipedia.org/wiki/Cubic_function#General_formula_for_roots
1d
comment Integral $\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$
Let us continue this discussion in chat.
1d
comment Integral $\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$
@Amad27, Just set $a+b-x=y$
1d
comment Integral $\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$
@Amad27, Yes. See also : math.stackexchange.com/questions/578957/… and math.stackexchange.com/questions/439851/…
1d
comment Integral $\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$
@Amad27, $f(x)+f(1+2011-x)=?$
1d
comment Integral $\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$
@Amad27, if $f(x)=\dfrac{\sqrt x }{\sqrt{2012 - x} + \sqrt x}, f(1+2011-x)=?$