In [6]:
import sympy as sp

In [11]:
x = sp.Symbol("x")
y = sp.Symbol("y")
z = sp.Symbol("z")

f = x**2 + sp.cos(y*z)

In [2]:
f.evalf(x=0)


---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-2-921d9cfb49ca> in <module>()
----> 1 f.evalf(x=0)

AttributeError: 'builtin_function_or_method' object has no attribute 'evalf'

In [26]:
from IPython.display import display, Math, Latex 

def Bra(tx):
    return "$$ \langle " +tx+ " \\rangle $$"
a = Bra("\psi")
Latex(a)


Out[26]:
$$ \langle \psi \rangle $$

In [ ]: