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location Buenos Aires, Argentina
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Sep
23
comment Calculation, disc in $\mathbb{C}$
Should that be $\frac{|t-z|^2}{|t-a|^2}$? Because if not, then the expression will, in general, be a complex number.
Sep
23
comment What is the relevance of the supremum in this question?
@dukenukem: Pretty much. Sometimes the supremum is written a little differently, like this: $\displaystyle \sup_{x\in I}|f(x)-g(x)|$. But it's the same thing.
Sep
23
answered What is the relevance of the supremum in this question?
Sep
23
suggested suggested edit on How to go about solving $((1+iz)/(1-iz))^4 = 1/2 + i\sqrt3/2$?
Sep
23
comment How do you explain the appearance of a sine in the integral for calculating the surface area of a sphere?
@Tpofofn: But where does the $2$, or, if you want, the $\sin \phi$ come from?
Sep
23
asked How do you explain the appearance of a sine in the integral for calculating the surface area of a sphere?
Sep
22
comment The zero vector
If you keep the requirement that addition and scalar multiplication are closed and ask for the subspace to be non-empty, then as a consequence zero must be in it. We just include that axiom to get rid of the empty set.
Sep
21
comment Question about solving 2nd order linear differential equations
What book are you using, by the way?
Sep
21
comment Question about solving 2nd order linear differential equations
@Korgan: If it turns out you were right, please tell us, because this is the method I've seen in every differential equations book there is. I'd be very surprised if it was wrong.
Sep
20
revised Showing vectors span a vector space by definition
Expanded answer
Sep
20
comment Showing vectors span a vector space by definition
This indeed uses only the defintion. I'll edit to make it more explicit.
Sep
20
answered Showing vectors span a vector space by definition
Sep
18
revised Basic set questions
Forgot to answer the last part
Sep
18
answered Basic set questions
Sep
8
answered Simplifying expression with absolute value and unknown
Aug
23
comment A question on Taylor Series and polynomial
I think the OP means that the Taylor series is finite.
Aug
22
answered In eigenvector calculations, why does $A-\lambda I$ need to be singular?
Aug
21
comment Graph $f(x)=\ln x+2$
@AustinBroussard: Yes, that's right.
Aug
21
comment Graph $f(x)=\ln x+2$
@AustinBroussard: I don't understand what you said about a horizontal asymptote having to do with $y \to \pm \infty$. A function has a horizontal asymptote, more or less, if it has a limit (not infinity) when $x$ goes to $\pm \infty$, and the logarithm doesn't have one. It simply goes to infinity.
Aug
21
comment Graph $f(x)=\ln x+2$
@AustinBroussard: This is a minor terminology thing. Rather than undefined, I would say that there is no y-intercept. The functions $\ln x$ and $\ln x + 2$ are undefined at $x=0$, so there is no y-intercept.