Analysis Fact
@AnalysisFact
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Daily tweets about real and complex analysis and related topics. From @JohnDCook.
Joined December 2009
A Cantor set is uncountable and yet can have Lebesgue measure zero (or positive measure).
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Winter is here, and it is time to take derivative with respect to x.
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To integrate the impossible integral
johndcook.com
An "impossible" integral creates an opportunity to discuss in what sense it is impossible and in what sense it is possible.
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Analytic functions dilate and rotate tiny disks, but can't flip them over. Complex conjugate is not analytic because it flips disks over.
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Fourier transform of a constant function https://t.co/L5Cdnzb8Do
johndcook.com
What is the Fourier transform of a constant function? What does it even mean? Two hand-wavy derivations and a rigorous formulation.
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Interpolation is generally more trustworthy than extrapolation.
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How to start with a minimal math library and bootstrap it to compute the functions not included
johndcook.com
How to start with a minimal math library and compute functions that are not included. e.g. how to use arc tangent to compute the other inverse trig functions.
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1/Γ(z) is an entire function, i.e. it is analytic everywhere in the complex plane.
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The Navigational Triangle Using spherical trig to calculate your position https://t.co/AlhvvjPXjc
johndcook.com
The navigational triangle has one vertex at your position, one at the North Pole, and one at the geographic position of a star. Solving this spherical triangle.
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