First things first: how do I get some help?

In [1]:

```
?
```

In [2]:

```
%quickref
```

In [3]:

```
%magic
```

In [4]:

```
%alias?
```

In [5]:

```
!pwd
```

Tab completion!

In [10]:

```
import numpy as np
np
```

Out[10]:

In [13]:

```
2+3
```

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In [14]:

```
_ **2
```

Out[14]:

In [17]:

```
2**100
```

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In [18]:

```
def factorial(n):
if n==0:
return 1
return n*factorial(n-1)
```

In [19]:

```
factorial(10)
```

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In [20]:

```
import this
```

This imports numpy as `np`

and matplotlib's plotting routines as `plt`

, plus setting lots of other stuff for you to work interactivel very easily:

In [21]:

```
%pylab inline
```

In [23]:

```
x = np.linspace(0, np.pi, 200)
y = np.sin(x**2)
plt.plot(x, y)
```

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```
```