I start ipython 7.3.0 on Windows 10 cmd.exe.

```
In [1]: from pylab import *
In [2]: %precision %e
Out[2]: '%e'
In [3]: exp(30)
Out[3]: 10686474581524.463
```

Grumble! Why don't I get scientific notation? It may be related to the fact that exp() is a numpy ufunc, and exp(30) is this a numpy float64 and not a plain python float64. Either way, frustrating that this doesn't "just work" with the ipython precision magic.