Python | sympy.rewrite() method

With the help of sympy.rewrite() method, we can represent any mathematical function in terms of another function.

Syntax: expression.rewrite(function)

Parameters:
expression – It is mathematical expression which is to be represented by another function.
function – It is the mathematical function used to rewrite the given expression.

Returns: Returns a mathematical expression corresponding to the input in terms of specified function.

Example #1:

# import sympy
from sympy import *

x = symbols('x')
expr = tan(x)
print("Expression = {}".format(expr))

# Use sympy.rewrite() method
expr_in_terms_of_sin = expr.rewrite(sin)

print("Expression in terms of sin() : {}".format(expr_in_terms_of_sin))

Output:

Expression = tan(x)
Expression in terms of sin() : 2*sin(x)**2/sin(2*x)

Example #2:

# import sympy
from sympy import *

x = symbols('x')
expr = factorial(x)
print("Expression = {}".format(expr))

# Use sympy.rewrite() method
expr_in_terms_of_gamma = expr.rewrite(gamma)

print("Expression in terms of gamma() : {}".format(expr_in_terms_of_gamma))

Output:

Expression = factorial(x)
Expression in terms of gamma() : gamma(x + 1)