Hi ,

I am in need of a help to

# I want to curve fit with two independent variables: Tag and Tau . I tried inputting variables with tuple but it did not work. I would be grateful if you could assist me in this regard. Here is my code:

```
import numpy as np
import matplotlib.pyplot as plt
from scipy.optimize import curve_fit
```

This is my model :

```
def concentration(T,a,b,c,d):
(Tag,Tau)= T return np.exp(a-d/Tag)/(np.exp(a-d/Tag) +np.exp(b-c/Tau))
```

Here I use a variable T which is a combination of two independent variables Tag and Tau. The output that I wish to fit is concentration.

```
T=[(7.9481e-04,5.9061e-04), (7.64438e-04,6.1231e-04), (7.64438e-04,6.04905e-04), (7.85453e-04,6.01268e-04) ]
experimental_concentration = [0.5428,0.798,0.75,0.70]
```

many thanks,

Swayam

## ···

**Swayam Prakash Sahoo**

### Universität Stuttgart

Germany