import math

def getValue(function, x):
    function = "val = " + function
    #compile(function, '', 'exec')
    exec(function)
    print(val)

function = input("Enter a function f(x):n")
getValue(function, 10)

>>> eval('math.sin(1)**2')
0.7080734182735712

>>> val
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'val' is not defined
>>> exec('val=math.sin(1)**2')
>>> val
0.7080734182735712

def getValue(function, x):
    function = "{}({})".format(function, x)
    print(function)
    val=eval(function)
    print(val)

import sys
import operator
from pyparsing import nums, oneOf, Word, Literal, Suppress
from pyparsing import ParseException, Forward, Group

op_map = { '*' : operator.mul,
           '+' : operator.add,
           '/' : operator.div,
           '-' : operator.sub}

exp = Forward()

number = Word(nums).setParseAction(lambda s, l, t: int(t[0]))
lparen = Literal('(').suppress()
rparen = Literal(')').suppress()
op = oneOf('+ - * /').setResultsName('op').setParseAction(lambda s, l, t: op_map[t[0]])

exp << Group(lparen + op + (number | exp) + (number | exp) + rparen)

def processArg(arg):
    if isinstance(arg, int):
        return arg
    else:
        return processList(arg)

def processList(lst):
    args = [processArg(x) for x in lst[1:]]
    return lst.op(args[0], args[1])


def handleLine(line):
    result = exp.parseString(line)
    return processList(result[0])

while True:
    try:
        print handleLine(raw_input('> '))
    except ParseException, e:
        print >>sys.stderr,
              "Syntax error at position %d: %s" % (e.col, e.line)
    except ZeroDivisionError:
        print >>sys.stderr,
              "Division by zero error"