34,845 reputation
12341
bio website jungenschaft-hohenstaufen.de
location Berlin, Germany
age 33
visits member for 3 years
seen Sep 17 at 22:31

Aug
7
reviewed Leave Open How to find rank of linear operator T on inner product space
Aug
7
reviewed Leave Open Multivariable-calculus, derivative and second derivative
Aug
7
reviewed Looks OK Is there an odd integer other than 1 that is the sum of its divisors?
Aug
7
reviewed Looks OK Limit Question: $\lim_{x \rightarrow a} \frac{3}{x}$. What does the “a” represent?
Aug
7
comment Limit Question: $\lim_{x \rightarrow a} \frac{3}{x}$. What does the “a” represent?
This not an answer to the question asked in my humple opinion. The OP does not asked for the value of the limit, but for the "role" of $a$ ...
Aug
7
reviewed Looks OK $x+y\sqrt{2}$ infimum ($x,y\in \mathbb{Z}$)
Aug
7
answered algorithm to find the root of a real-valued function $f$
Aug
7
comment How to find rank of linear operator T on inner product space
You can $Tv = (v,\beta)\gamma$. When is this a multiple of $v$? (Note that it is always a multiple of $\gamma$!
Aug
7
comment Does “uniformly isolated” imply closed?
@goblin Better? Rephrased it a little.
Aug
7
answered Find the exact values without using a calculator of cos^-1(-1/2), tan^-1(-√3/3) and sec^-1 (2)
Aug
7
answered Does “uniformly isolated” imply closed?
Aug
7
answered How to find rank of linear operator T on inner product space
Aug
7
answered Prove that the function $f^2+f^3$ attains every complex value.
Aug
7
answered Multivariable-calculus
Aug
7
comment Closed form for recurrence relation
The characteristic roots are (according to maple) \begin{align*} x_1 &= \frac{\bigl(108 + 12\sqrt{69}\bigr)^{2/3} + 12}{6\cdot \bigl(108 + 12\sqrt{69}\bigr)^{1/3}} \\ x_2 &= \frac{\bigl(108 + 12\sqrt{69}\bigr)^{2/3}(-1 + \sqrt{3}i) - 12(1 + \sqrt3 i)}{12 \cdot \bigl(108 + 12\sqrt{69}\bigr)^{1/3} }\\ x_3 = \overline{x_2} &= \frac{\bigl(108 + 12\sqrt{69}\bigr)^{2/3}(-1 - \sqrt{3}i) - 12(1 - \sqrt3 i)}{12 \cdot \bigl(108 + 12\sqrt{69}\bigr)^{1/3} } \end{align*}
Aug
7
comment How to find adjoint of linear operator T on inner product space V
The inner product is linear, $(\alpha,\beta)$ is just a scalar, let for a momoent $a := (\alpha, \beta) \in \mathbb C$. Then $$\bigl((\alpha, \beta)\gamma, \delta\bigr) = (a\gamma, \delta) = a(\gamma,\delta) = (\alpha,\beta)(\gamma, \delta) $$
Aug
7
answered How to find adjoint of linear operator T on inner product space V
Aug
7
comment convex weak* sequentially closed subset of a separable Banach space implies weak* closed
@niki Added something. Does this help?
Aug
7
revised convex weak* sequentially closed subset of a separable Banach space implies weak* closed
Addendum - constructing a subsequence.
Aug
7
reviewed Leave Closed probability of collision with randomly generated ID