# Please help me to draw f(x) = sin(x) if x<=0 and f(x)=cos(x) if x>1

thanks for your answers

Please help me to draw f(x) = sin(x) if x<=0 and f(x)=cos(x) if x>1

thanks for your answers

add a comment

2

`plot(sin(x), (x, -10, 0)) + plot(cos(x), (x, 1, 10))`

. By the way, I don't know if the question contains a typo or if there is not supposed to be a plot when x is between 0 and 1.

2

There are a few options. One is to use the `piecewise`

command:

```
f=Piecewise([[(-10,1),sin(x)],[(1,10),cos(x)]],x)
plot(lambda x: f(x),(-2*pi,2*pi))
```

Another is to use a python function definition:

```
def f(x):
if x<=1:
return(sin(x))
else:
return(cos(x))
plot(f,(-2*pi,2*pi))
```

Note that with the python function definition, the `plot`

command must be called just with `f`

and not `f(x)`

. Calling with `f(x)`

causes python to evaluate $f$ before doing the plot and will result in an incorrect plot.

More compactly, you could also use a lambda expression: `lambda x: sin(x) if x `<`= 1 else cos(x)`

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Asked: ** 2013-06-12 14:33:24 +0200 **

Seen: **2,147 times**

Last updated: **Jun 12 '13**

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