There is an operator missing, likely a `*`

:

```
-3.7 need_something_here (prof[x])
```

The “is *not callable*” occurs because the parenthesis — and lack of operator which would have switched the parenthesis into precedence operators — make Python try to *call* the result of `-3.7`

(a float) as a function, which is not allowed.

The parenthesis are also not needed in this case, the following may be sufficient/correct:

```
-3.7 * prof[x]
```

As Legolas points out, there are other things which may need to be addressed:

```
2.25 * (1 - math.pow(math.e, (-3.7(prof[x])/2.25))) * (math.e, (0/2.25)))
^-- op missing
extra parenthesis --^
valid but questionable float*tuple --^
expression yields 0.0 always --^
```