Jp McCarthy
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 11h comment Quadratic inequality (Sign Reversal?) You are much better off considering the geometry of the quadratic to see it is positive "outside" the roots...if you set it up as quadratic > 0 2d revised Bounding a sum involving a $\Re((z\zeta)^N)$ term deleted 7 characters in body Apr 26 comment Bounding a sum involving a $\Re((z\zeta)^N)$ term @charMD thanks - I had it written up elsewhere and wasn't careful with the constant. It can be shown using the secant to tangent identity and if you search this site there is a sum of tangent-squared identity. Apr 26 revised Bounding a sum involving a $\Re((z\zeta)^N)$ term added 137 characters in body Apr 24 comment FUNCTIONS : Theoretical Doubt Rather than one number sent to one number --- such as $f(x)=x^2$ sends $x=3$ to $f(x)=3^2=9$ --- it is a pair of numbers sent to a single number. For example, the area of a rectangle function which takes the pair $(x,y)=(\text{height},\text{width})$ to $xy$ and we write $f(x,y)=xy$. Apr 23 comment When is this sine function differentiable at all points? Double root...cough, cough. Apr 20 revised Bounding a sum involving a $\Re((z\zeta)^N)$ term edited title Apr 18 comment How to call a partition of $X$ which consists of all singleton subsets of $X$? +1 for "partition of singletons" or "singleton partition" Apr 18 comment “Inverse” of a step function Input a negative number, then a number between zero and one and finally a number larger than one. Apr 17 comment “Inverse” of a step function $u(t)-u(t-1)$... Apr 17 comment “Inverse” of a step function Think of the unit step as a switch...add to turn it on and then subtract to turn it off... Apr 15 revised Bounding a sum involving a $\Re((z\zeta)^N)$ term added 52 characters in body Apr 11 comment What is a representation? A homomorphism from the group into a matrix group. Apr 9 answered Solutions to the complex equation z^n=w with one solution given Apr 8 comment Show that there exists a positive integer $k$ such that $g^k=1_G$ en.wikipedia.org/wiki/Pigeonhole_principle Apr 8 asked Bounding a sum involving a $\Re((z\zeta)^N)$ term Apr 8 revised Simplifying this (perhaps) real expression containing roots of unity deleted 1 character in body Apr 8 revised Simplifying this (perhaps) real expression containing roots of unity added 361 characters in body Apr 8 comment Simplifying this (perhaps) real expression containing roots of unity Thank you... the $\sec^2$ term actually came from what you have at the end here. Apr 8 accepted Simplifying this (perhaps) real expression containing roots of unity