📜  sympy 函数定义 - Python (1)

📅  最后修改于: 2023-12-03 15:35:13.548000             🧑  作者: Mango

Introduction to Symbolic Mathematics with Sympy in Python

Sympy is a Python library for symbolic mathematics that aims to be an alternative to systems like Mathematica and Maple. It has a wide range of functionalities, including calculus, algebraic manipulation, equation solving, and more.

To use Sympy, you first need to import it:

import sympy as sp
Defining and Manipulating Functions

One of the main features of Sympy is the ability to define and manipulate mathematical functions symbolically. To define a function, you can use the sp.Function class:

x = sp.Symbol('x')
f = sp.Function('f')(x)

Here, we've defined a function f of the variable x using the sp.Function class. Note that we also had to define x as a Symbol using the sp.Symbol class.

We can now use this function to perform algebraic manipulations symbolically. For example, let's compute the derivative of f(x) with respect to x:

df_dx = sp.diff(f, x)

This will give us the derivative of f(x) with respect to x, which we can then simplify using the sp.simplify function:

simplified_df_dx = sp.simplify(df_dx)
Solving Equations

Sympy can also solve equations symbolically. For example, let's solve the equation x^2 - 1 = 0:

solution = sp.solve(sp.Eq(x**2 - 1, 0), x)

Here, sp.Eq is used to create an equation object that we want to solve, and sp.solve is used to solve the equation for x. The result will be a list of solutions, which we can then print:

print(solution)
Conclusion

Sympy is a powerful library for symbolic mathematics in Python. It allows us to manipulate mathematical functions and solve equations symbolically, which can be useful in many applications.