305,011 reputation
24275556
bio website
location
age
visits member for 3 years, 10 months
seen 47 mins ago

Dec
14
revised Prove or disprove this lemma for Catalan Numbers
added 242 characters in body
Dec
14
answered Prove or disprove this lemma for Catalan Numbers
Dec
14
comment Trig Substitution and Integration square root divided by polynomial squared
As it reads now, don't need no trig, just $\sqrt{x^2}=x$ if $x$ is positive, $=-x$ if $x$ is negative.
Dec
14
comment Predicate Logic Interpretation/Modelling help
You are welcome. There are harder things! Right now is just language lesson, the meaning of $L$-structure and of "$\varphi$ is true in $M$."
Dec
14
comment Predicate Logic Interpretation/Modelling help
All that you have written is right,
Dec
14
comment Factor $17i$ into a product of irreducible elements in $Z[i]$
$17=(4+i)(4-i)$. Each is irreducible in $\mathbb{Z}[i]$ since it has prime norm.
Dec
14
reviewed Leave Open Demostrate: $M_p=2^p-1$
Dec
14
reviewed Leave Open solving the limit $\lim (\frac{x}{x-1}-\frac{1}{\ln x})\, \, \text{as } x\to1$
Dec
14
reviewed Leave Open probability than in a given deal 2 players get 2 aces and 2 players have no aces.
Dec
14
reviewed Leave Open A reduction formula for $\int_0^1 x^n/\sqrt{9 - x^2}\,\mathrm dx$
Dec
14
reviewed Leave Open Solving $\lim_{x\to0}\frac{e^x-1}{\sin x}$
Dec
14
reviewed Leave Open For which $s\in\mathbb R$, is $H^s(\mathbb T)$ a Banach algebra?
Dec
14
answered probability than in a given deal 2 players get 2 aces and 2 players have no aces.
Dec
13
comment sine and cosine and difference of angles
I am puzzled. If $x$ is first quadrant and $y$ is second quadrant then $\sin(x-y)$ should be negative.
Dec
13
revised If $p\equiv 2$ mod $3$, $x^{3}\equiv a$ mod $p$ has only one solution modulo $p$.
added 6 characters in body
Dec
13
answered If $p\equiv 2$ mod $3$, $x^{3}\equiv a$ mod $p$ has only one solution modulo $p$.
Dec
13
answered Two conjectures regarding $\varphi(n)$
Dec
13
answered Finding the rate of change of a relation at $x=1$
Dec
13
comment Finding the rate of change of a relation at $x=1$
The first method is wrong, if you want to find rate of change, you do not first "freeze" $x$. And setting the result equal to $0$ is for no reason. The second is almost right, and there are two possible values of $y$, with two different slopes. For some reason you wrote $\frac{dx}{dy}$ instead of $\frac{dy}{dx}$.
Dec
13
comment To prove $(\sin\theta + \csc\theta)^2 + (\cos\theta +\sec\theta)^2 \ge 9$
The argument is correct, both terms are $\ge 4$. But there is interaction, the equality case of AM/GM cannot hold simultaneously for both parts.