# TypeError: unsupported operand type(s) for ** or pow(): 'list' and 'sage.symbolic.expression.Expression'

When I enter following command in Sage Notebook;

```
var('x k w')
f = x^3 * e^(k*x) * sin(w*x)
show(f)
show(f.diff(x))
```

I get this error

```
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-12-e1add3252393> in <module>()
1 var('x k w')
----> 2 f = x**Integer(3) * e**(k*x) * sin(w*x)
3 show(f)
4 show(f.diff(x))
TypeError: unsupported operand type(s) for ** or pow(): 'list' and 'sage.symbolic.expression.Expression'
```

How can I resolve this issue.