Psi power

The economists among youse certainly know of the gamma function, the analytic construction of the arithmetic factorial function: n Gamma(n) = Gamma(n+1).

How about this function: psi(n) = d/dn ln Gamma(n).

Why is it interesting? (Those of you who have memorized the Chemical Rubber Company Handbook of Mathematical Tables or a similar encyclopedia, please abstain.)

2 comments:

  1. I'll abstain, but here's a hint: if you remember why slide rules work, you're more than half way to the answer.

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  2. "The economists among youse..."

    Wabulon, you've learned to talk Brooklyn!

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