I'm making a program that uses derivates to calculate an error.

I keep getting this error : 'Mul' object has no attribute 'sp'.

The solutions to this error that i've found so far are when people import everything from sympy and math (from sympy/math import *) because both sympy and math have a sin() function.

But as you can see from my code bellow i don't have it like that and the error still shows up, why?

```
import sympy as sp
from math import factorial
def F(x):
return 4*(x**2)+sp.sin(9*x)
sp.init_printing()
x=sp.symbols('x')
def D1(x1):
return(sp.diff(F(x),x,1).sp.subs(x,x1))
def D2(x1):
return(sp.diff(F(x),x,2).sp.subs(x,x1))
def D3(x1):
return(sp.diff(F(x),x,3).sp.subs(x,x1))
def maxD3(x1,x2):
if(D3(x1)>D3(x2)):
return D3(x1)
else:
return D3(x2)
erro1 = (1/factorial(3))*maxD3(-1,1)*abs((0.3-(-1))*(0.3-1))
erro1 = (1/factorial(3))*maxD3(-1,1)*abs((0.83-(-1))*(0.83-1))
print("Erro f(0.3): ", erro1)
print("Erro f(0.83): ", erro2)
```

Also have changed "from math import factorial" to "import math as math" and the error also keeps showing up.

I'm using Python 3.6.1.

EDIT: Full Traceback

```
Traceback (most recent call last):
File "main.py", line 24, in <module>
erro1 = (1/math.factorial(3))*maxD3(-1,1)*abs((0.3-(-1))*(0.3-1))
File "main.py", line 19, in maxD3
if(D3(x1)>D3(x2)):
File "main.py", line 16, in D3
return(sp.diff(F(x),x,3).sp.subs(x,x1))
AttributeError: 'Mul' object has no attribute 'sp'
```

This is the corrected version of your code

Output on my system:

Is this the expected output?

Also, you don't need to import everything from sympy. You can just import what you need. Example: