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Jan
19
comment Why “even number of elements in Group” in this question is given?
For the simplest counterexample, suppose that $G$ consists of a single element.
Jan
18
revised How does $ln(y) = 2x+C$ become $y = e^{2x+C}$?
Latex formatting, tried to make it clear what was in the exponents.
Jan
18
suggested approved edit on How does $ln(y) = 2x+C$ become $y = e^{2x+C}$?
Jan
18
comment Double inequality with square root
Was that supposed to be $1-\sqrt\alpha<0<1+\sqrt\alpha$?
Jan
17
comment Help with Baby Rudin Excercise 3.17. Partial converse to the fact that convergence impiies Cesaro summability. Warning: Pretty involved problem.
Right, since $\epsilon$ is fixed in advance, we've shown that the term goes to zero no matter how small $\epsilon$ is.
Jan
17
revised Orthogonal complement of the kernel of $u\in B(H, H')$
added 610 characters in body
Jan
17
answered Orthogonal complement of the kernel of $u\in B(H, H')$
Jan
17
answered Help with Baby Rudin Excercise 3.17. Partial converse to the fact that convergence impiies Cesaro summability. Warning: Pretty involved problem.
Jan
17
awarded  Explainer
Jan
17
comment Is this expression even a function?
Yes, that's right. If you ask, "Is this a function?" without specifying a domain, we assume the domain is everything for which the expression is defined and only consider the uniqueness condition. Once you include the domain $A$ in the question, you can ask whether $f(x)$ even makes sense for every $x$ in $A$. A couple more examples: $f(x)=\pm x$ is not a function on $\mathbb{R}$. But it is a function on the set $\{0\}$. $g(x)=\frac{1}{x}$ is not a function on $\mathbb{R}$. But it is a function on $\mathbb{R}\setminus \{0\}$.
Jan
17
revised Is this expression even a function?
Removed extraneous tags.
Jan
17
comment Is this expression even a function?
If you assume that $A=B=\mathbb{R}$, then $f$ is not a function from $A$ to $B$, which is what is important for your problem. But $f$ is still a function on domains not containing $-2$, since $f$ takes on a exactly one value for every other real number.
Jan
17
suggested approved edit on Is this expression even a function?
Jan
17
revised Is this expression even a function?
Latex formatting.
Jan
17
answered Is this expression even a function?
Jan
17
suggested approved edit on Is this expression even a function?
Jan
17
answered $\int_0^{\infty}y^2e^{-y} dy$
Jan
17
awarded  Informed
Jan
17
revised In the formula $Ax+By=C$, is it true that $A$ and $B$ can't both be zero? If so, why not?
deleted 3 characters in body
Jan
17
answered In the formula $Ax+By=C$, is it true that $A$ and $B$ can't both be zero? If so, why not?