Natural Logarithm algebra in numpy

Question

I have the following equation:

import numpy as np

d = (x - y) / np.log((x - z) / (y - z))

Where I am trying to find x

Is this possible in numpy or other python libraries? In this case, could you please provide sample code of how to do it with this specific problem?

You can use `sympy` to find $x(d,y,z)$ and then calculate it using `numpy`. — Liran Funaro, Mar 14 '19 at 21:36
When i try to paste x(d,y,z)$ in the terminal (even after setting dummy variables x = 50, y = 40, z = 30) I get "invalid syntax" error after running the code. sympy was imported as well — HerrSober, Mar 14 '19 at 21:46

Albert Alonso · Accepted Answer · 2019-03-14T21:49:02.423

3

I would probably use just sympy and their solver: sympy Library Solver

from sympy import solve, log, exp
from sympy.abc import x,y,z,d

f = (x - y) / log((x - z) / (y - z)) - d

solution = solve(f, x)

And the output is giving me is

[-d*LambertW(-(y - z)*exp(-(y - z)/d)/d) + z]

edited Mar 14 '19 at 21:49

answered Mar 14 '19 at 21:43

Albert Alonso

fantastic! works. thanks for introducing me to this library! – HerrSober Mar 14 '19 at 21:54

1 Answers1