# Tag Info

1 vote

### Is a four-variable function less than one?

The command FindInstance[{f >= 1, x >= 0, w >= 1, y > 0, z > 0}, {w, x, y, z}] returns {} which, if one trusts ...

### Chi-square minimization error

The problem is caused by "NDSolve". It should localize the dummy variable "t", but fails to do so. Consider: ...

### Chi-square minimization error

Three comments: solve for all variables simultaneously instead of solving for $(x,y,z)$ first and $w$ second, use NonlinearModelFit instead of writing your own ...
Accepted

### Optimizing an ODE fitting algorithm with interpolated data

Another way to do the fitting. 1 - We will using a custom-made second order interpolation as giving in f[t]. A dummy extra data point was introduced to facilitate ...

### Optimizing an ODE fitting algorithm with interpolated data

This problem has 4 parameters, and only 6 x 3 = 18 data points. I suspect that this problem is only weakly determined, if you consider the "Rule of 10" which states that you should have 10 ...
Accepted

### 'The objective function is not a scalar' in NMinimize

You define beta in NMinimize as a scalar. Replacing beta by: 1 and evaluating: ...
1 vote

### Why hasn't the minimum value of a+b been determined?

As the first condition is actually an equation, we may solve for b: sol=Solve[9 == 9^(1/a) 3^(4/b), b][] As we want real numbers, we can delete the imaginary ...