show() smashes multiplied numbers together so the product looks like a number

<div id="comment:0"></div>

To see this, evaluate the following in a notebook cell:

```
var('r,z')
a=(r*z^2).integrate(z,0,r).integrate(r,0,sqrt(9/2))*2*pi
a.show()
print a
```

Firefox 3 Beta 5; Ubuntu 8.04

Component: **calculus**

_Issue created by migration from https://trac.sagemath.org/ticket/3202_

