# TypeError: 'sage.rings.integer.Integer' object is not callable

Hi there.

I am new to SAGE and I am getting this error when doing an integration. I am not sure if I am doing correctly the power 2 of the sech function.

I defined `f`

function and my code is:

```
var('c,H,k,d,x,t')
f=(c * H * (sech^2(k / d * (x - c * t))))/(d + H * (sech^2(k / d*(x - c * t))))
f.integral(t)
```

The error is:

```
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "_sage_input_7.py", line 10, in <module>
exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + support_.preparse_worksheet_cell(base64.b64decode("dmFyKCdjLEgsayxkLHgsdCcpCmY9KGMgKiBIICogKHNlY2heMihrIC8gZCAqICh4IC0gYyAqIHQpKSkpLyhkICsgSCAqIChzZWNoXjIoayAvIGQqKHggLSBjICogdCkpKSkKZi5pbnRlZ3JhbCh0KQ=="),globals())+"\\n"); execfile(os.path.abspath("___code___.py"))
File "", line 1, in <module>
File "/tmp/tmpGxgMcP/___code___.py", line 4, in <module>
f=(c * H * (sech**_sage_const_2 (k / d * (x - c * t))))/(d + H * (sech**_sage_const_2 (k / d*(x - c * t))))
TypeError: 'sage.rings.integer.Integer' object is not callable
```

Any corrections and/or suggestions will be welcome. Thanks in advance.

P.S. - Hope the edit improved the reading of the topic, but could not find how to display colors as you did in TypeError, etc.

UPDATE:

So after correcting the `sech`

above to `sech(x)^2`

, I calculate the integral of `f`

between the limits 0 and t, and changed the second line of the code above to:

```
limit(f=(c * H * (sech(k / d * (x - c * t))^2))/(d + H * (sech(k / d*(x - c * t))^2)),t=t)
```

Now I get the following errors:

```
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "_sage_input_18.py", line 10, in <module>
exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("dmFyKCdjLEgsayxkLHgsdCcpCmxpbWl0KGY9KGMgKiBIICogKHNlY2goayAvIGQgKiAoeCAtIGMgKiB0KSleMikpLyhkICsgSCAqIChzZWNoKGsgLyBkKih4IC0gYyAqIHQpKV4yKSksdD10KQpmLmludGVncmFsKHQp"),globals())+"\\n"); execfile(os.path.abspath("___code___.py"))
File "", line 1, in <module>
File "/tmp/tmpJsB9eB/___code___.py", line 4, in <module>
limit(f=(c * H * (sech(k / d * (x - c * t))**_sage_const_2 ))/(d + H * (sech(k / d*(x - c * t))**_sage_const_2 )),t=t)
TypeError: limit() takes at least 1 argument (0 given)
```

Any idea what is wrong here?

The syntax of limit seems correct but how to specify both limits of 0 and t for the integral?

Thanks in advance.