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bio website reddit.com/r/…
location meatspace
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visits member for 2 years, 6 months
seen 2 days ago

when someone smiles at me, all I see is an ape bearing its teethe


Apr
9
comment Prove or Disprove that $\left|\frac{e^{2i\theta} -2e^{i\theta} - 1}{e^{2i\theta} + 2e^{i\theta} -1}\right| = 1$
@ Pedro Tamaroff: I remember those times fondly when you pooped on my chest =)
Apr
8
comment Using the Residue Theorem for a contour integral along the Riemann sphere
I'm busy nuttin', and she still suckin'
Mar
30
comment Limit of infinite loops of sin x as n tends to infinity
Maybe use the fact that for $x\neq0$, $|\sin(x)|<|x|$. Also that $\sin(x)$ is strictly monotonically increasing on $[-1,1]$.
Mar
11
comment Prove the set of sequences $c_0$ which converge to zero in $l_{\infty}$ is closed.
you're right I mis-typed it, I'll fix.
Mar
11
comment Prove the set of sequences $c_0$ which converge to zero in $l_{\infty}$ is closed.
damn that's slick.
Jan
29
comment Prove this matrix is invertible for $n < m-1$
awesome answer, thanks.
Nov
3
comment Singularities in (Elementary) Real Algebraic Geometry
The cubic is $y^3+2y^2+y+(v-u^2)=0$, the roots will be $functions$ of $u$ and $v$, that's what I'm after, so that I can prove that $f(x,y)=(u(x,y),v(x,y))=(x,x^2-(y+1)^3+(y+1)^2)$ has an inverse which is analytic.
Nov
3
comment Singularities in (Elementary) Real Algebraic Geometry
I'm having trouble understanding. Solving $v=f(u,y)$ for $y$ will give me 3 roots, each a function of $u$ and $v$, I should expect that one of these roots is a real analytic function in a nbhd of $(0,0)$, correct?
Oct
5
comment Prove that $\frac{d}{dx}\int_0^xf(x,y)dy = f(x,x)+\int_0^x\frac{\partial}{\partial x}f(x,y)dy$
super slick! =o
Sep
25
comment Let $b_n$ decrease monotonically to zero, prove $\sum b_nz^n$ converges for $|z|\leq 1$ and $z\neq 1$
@njguliyev oh nice, that does it right there, thanks.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
oh shoot you're right, ok that makes sense.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
not off the top of my head no, we've just been using this condition without explanation in a numerical optimization class.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
Are you sure? The wikipedia article doesn't mention it.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
I don't know about other conditions, I'm basing this off of en.wikipedia.org/wiki/… I guess it says the Hessian must be invertible as well.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
@JonathanY. I'm having trouble seeing how this shows positive curvature in all directions.
Sep
21
comment Prove that if the Hessian of $f$ is positive definite at $a$, then the function attains a minimum at $a$
You're right, I guess I should have specified for $n\geq 2$.
Aug
14
comment Calculating a probability mass function (sufficient statistic)
@AlexR. ahh ok, well that would explain my inconsistent results, thanks.
Aug
14
comment Calculating a probability mass function (sufficient statistic)
@AlexR. so you're saying that $T$ is not a random variable taking values in $1,...,n$ depending on which $X_k$ is the smallest, but instead takes the value of $X_{(1)}$?
Aug
8
comment Help Proving that $\frac{(1+\frac{1}{t})^t}{e} = 1 -\frac{1}{2t} + O(\frac{1}{t^2})$ for $t\geq 1$
Ansturm is now banned.
Jul
21
comment Sampling 100 widgets to test for defective ones
Yah that's right. I believe their reasoning would have been correct if the $P(B_i)$ were uniform for all $i$, but since $P(B_6)$ is very small compared to $i$'s closer to $50$, their reasoning isn't correct.