Approximating Hyperbolic Tangent

Survey of fast tanh approximations using Taylor series, Padé approximants, splines, and bitwise manipulation techniques like K-TanH and Schraudolph

Not all elementary functions can be expressed with exp-minus-log

a personal blog

🌀 Today’s dive into ζ′/ζ
Spent the morning peeling back another layer of the zeta function. Turns out: if you zoom in on height t, only the zeros ρ with ∣𝑡ᵨ−𝑡∣≤1 really matter (𝐼𝑚(ρ)=𝑡ᵨ) — everything else dissolves into a clean O(log⁡∣t∣) haze.
It’s wild how much structure hides behind a single identity: \( \frac{\zeta'(s)}{\zeta(s)}
= -\frac{1}{s-1}
+ \sum_{\rho:\, |t_\rho - t|\le 1} \frac{1}{s-\rho}
+ O(\log(|t|+4)). \)
Not easy stuff, but exactly the kind of scaffolding we can build on top of The Riemann Hypothesis Revealed. Every step makes the landscape a little less mysterious.
Onward.
🔗https://cortexdrifter.blogspot.com/2026/04/a-small-taste-from-my-new-book-season-2.html

#AnalyticNumberTheory #MathBlog

A Small Taste from My New Book: Season 2 Episode 7

Explorations in analytic number theory, asymptotic analysis, and unsolved problems, written by a mathematician and software engineer.

Jensen’s formula as a microscope 🔍
By mixing geometry, analytic growth, and symmetry, we get tight control on local zero fluctuations in the critical strip—and a clean logarithmic bound emerges.
This is A Small Taste from My New Book — Season 2, Episode 6.
The machinery is set. Now let’s see what it reveals next.
🔗 https://cortexdrifter.blogspot.com/2026/03/a-small-taste-from-my-new-book-season-2_28.html
#RiemannHypothesis #AnalyticNumberTheory #MathBlog #JensensFormula
A Small Taste from My New Book: Season 2 Episode 6

Explorations in analytic number theory, asymptotic analysis, and unsolved problems, written by a mathematician and software engineer.

Carnival of Mathematics 210

This month’s Carnival is hosted right here at The Aperiodical, and rounds up interesting internet maths content from the month of October 2022.

The Aperiodical