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 Apr5 comment Complexity of $\gcd$ algorithm @BrianM.Scott Thank you very much. Apr4 comment Creating random numbers matching mean and standard deviation For some reason, when reading the question I presumed he was asking for a normal distribution. I don't know why... Mar30 comment circle as polar coordinates @snowman There is indeed no answer. In mathematics the method is usually problem-dependent. From my point of view, what I did is more straightforward, as I'm just calculating the integral, of course a lot of times you solve integrals by doing changes of variables that are not simple isometries such as a translation-rotation. You just have to look in each case which is the best method. In this particular case the integrand is just $r$ in polar coordinates, so trying to evaluate the area of integration in those coordinates seemed to be a better option. Mar30 comment circle as polar coordinates @snowman What you do is equivalent to translating the circle (and the function) to the left so the circle is centered at the origin. That should give the same result. What I did was just evaluate the function in the area in which we're integrating. Mar30 comment circle as polar coordinates @snowman I edited the answer with further details about that. Mar24 comment About this congruence implication you mean when $X=0$?, then it's just Fermat's little theorem. Mar24 comment About this congruence implication Thank you so much. The second one was unneccessary, but I was reading it in a paper and they said that that was an implication of both equations. Thank you again Mar12 comment Help visualizing this quotient space I was seeing that cylinder, just wanted to be able to visualize that "wrapping and stretching" a little bit better. Jun27 comment Topologies on n-manifolds Well... by definition of a manifold, any topology of a manifold must the same topology (o equivalent) to the usual topology, as it must be locally homeomorphic to $\mathbb R^n$ with the usual topology. Jun25 comment Geodesics of this metric Ok, I see it. Thank you very much Jun25 comment Geodesics of this metric Thank you. How do you get from $\ddot x-C^2 /x^3=0$ to the solution $x(t)$? Jun24 comment Let $G=\mathbb Z_4 \times \mathbb Z_2$. Find all $H$ subgroups of $G$ of order 2, so that $G / H$ is cyclic. Oh that was your question... I'm sorry, well We already found all the subgroups of order $2$, now do you hav any problem in computing the quotient groups $G/H$ Checking if it' cyclic is checking if the identity $H$ generates the whole group $G/H$. Jun24 comment Help understanding a proof in differential geometry I see your "firstly", I just don't see why it's neccesary in the argument. The fact that there are a finite number of points in which $df$ is singular comes from the expression of $P'$, right? Jun24 comment Help understanding a proof in differential geometry Thank you both, it was a lot simpler than I thought. Jun19 comment How to prove a $k$-$1$ differential form is simple Ok, I think I got it. Thank you. Jun19 comment How to prove a $k$-$1$ differential form is simple I see that particular case, thank you. I was trying to relate the fact that 1 forms are obviously simple and that the space they span has the same dimension as the space of k-1 forms. Jun19 comment How to prove a $k$-$1$ differential form is simple @ReneSchipperus I'm sorry, in your first comment, with both you were talking about the space of $k$-$1$ forms and what else? Jun19 comment How to prove a $k$-$1$ differential form is simple @ReneSchipperus Hm? I see they must be a linear combination of the $k$ linearly independent $k$-$1$ forms, but I don't see it. I promise I've given it many thoughts. And the fact I've always seen it stated without proof makes me feel stupid xD Jun19 comment How to prove a $k$-$1$ differential form is simple @ReneSchipperus Yes, but is that enough? I don't see it. Jun14 comment Book recommendations for someone interested in higher mathematics? I first learnt group theory (only finite groups), then topology, and then more group theory (more about representation theory and continous groups). As for analysis, I've never learnt more than what a regular physicist studies, and I notice a lack of knowledge I would like to get rid off :)