Sunday, February 6, 2022

HP 17BII+ and TI-84 Plus CE Python: Zeta Approximation

HP 17BII+ and TI-84 Plus CE Python:  Zeta Approximation


Zeta Function


zeta(x) = Σ(1 ÷ (n^x), n =1 to ∞)


We are going to use the approximation:


zeta(x) = Σ(1 ÷ (n^x), n =1 to w) where w = intg(10^((a + 2) ÷ x)


where a is the number of decimal places desired.  The higher the accuracy, the longer the calculation takes.  Also the lower x is, the longer the calculation takes.


This is for all x > 0.


HP 17BII+ Formula ZETA


ZETA=0×L(W:10^IP((ACC+2)÷X))+Σ(N:1:G(W):1:INV(N^X))


Examples:


ACC =3, X = 2;  Result:  ZETA = 1.63


ACC =3, X = 3.5;  Result:  ZETA = 1.13


ACC =3, X = 8.7;  Result:  ZETA = 1.00


TI-84 Plus CE Python:  zeta.py


# 2021-12-07 ews

# zeta function approximation

from math import *

print("zeta function approximation")

x=eval(input("x? "))

a=eval(input("# places? "))

w=int(10**((a+2)/x)

z=0

n=1

while n<w:

  z+=(n**x)**-1

  n+=1

z=round(z,a)

print("zeta = "+str(z))


Eddie


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