Kristofu0019214 Asks:

For some reason, I cannot render the 2-parameter logistic item characteristic curve equation with the given parameters a = 13.67 and b = -1.58.

*Function curve not rendering correctly*For some reason, I cannot render the 2-parameter logistic item characteristic curve equation with the given parameters a = 13.67 and b = -1.58.

I use the given code.

Code:

```
documentclass{report}
usepackage{pgfplots}
begin{document}
begin{figure}[h]
begin{center}
begin{tikzpicture}
begin{axis}[
enlargelimits=false,
xlabel={$theta$},
ylabel={probability},
xmin=-7, xmax=7,
ymin=-0.5, ymax=1.5,
legend pos=north west,
legend entries={test}
]
addlegendimage{gray}
]
addplot [smooth, gray, domain=-10:10]{exp(13.67*(x+1.58))/(1 + exp(13.67*(x+1.58)))};
end{axis}
end{tikzpicture}
end{center}
end{figure}
end{document}
```

And this is the output.

However, when I graph the same function on Desmos, it doesn’t look as ugly…

The logistic functions isn’t supposed to be above 1 or below 0. What am I doing wrong so that the output is so off on LaTeX?

Thanks in advance!

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