Hi,

I want to make a fitting curve just like '' y=A+B*Log[x^n] '' from the experimental data, but it always doesnt work...

Here it is:

data = {{0 , 100}, {0.0008, 126.992}, {0.00195, 147.187}, {0.0033, 164.79}, {0.005, 181.877}, {0.007, 198.982}, {0.01, 219.833}, {0.015, 246.441},{0.02, 278.042}, {0.027, 308.821}, {0.037, 341.473}, {0.047, 362.767}, {0.06, 379.048}, {0.08, 394.5}, {0.1, 405.422}, {0.12, 412.5}, {0.14, 415}, {0.17, 418}, {0.2, 420}, {0.24,

421}, {0.282, 422}}

model = a + b Log[x^n]

funk = FindFit[data, model, {a, b, n}, x]

and this is the warning:

FindFit::nlnum: The function value {Indeterminate, -133.123, -152.427, -169.504, -186.175, -202.944, -223.438, -249.641, -280.954, -311.433, <<11>>} is not a list of numbers with dimensions {21} at {a, b, n} = {1, 1, 1}.

I used the order to prove the data is numerical, but have no idea what the nonrectangle means...

Thanks a lot!

[IMG]file:///c:/temp/moz-screenshot-2.jpg[/IMG]