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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