Javier
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 Sep 23 suggested rejected 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. Aug 21 answered Graph $f(x)=\ln x+2$ Aug 21 comment Graph $f(x)=\ln x+2$ Don't you mean $\ln x + 2$, or maybe $\ln(2+x)$? Aug 13 comment Why can't $\int_0^1\sin(x^2) dx$ be equal to $2$? Forgive me if I'm missing something, but why would it be 2? I mean, with so many numbers to choose from, why would you expect it to be 2?