python - Sympy 返回 log 而不是 ln

Question

我有这个等式:

import sympy as sp

x = sp.Symbol(‘x’, real = True)
fx = sp.log(x,3)

sp.diff(fx, x) 

Sympy 返回:

1/(x*log(3))

Sympy 应该返回:

1/(x*ln(3))

为什么 Sympy 返回对数函数而不是自然对数函数？

Answer 1

来自here :

Note:

In SymPy, as in Python and most programming languages, log is the natural logarithm, also known as ln. SymPy automatically provides an alias ln = log in case you forget this.

>>> sp.ln(x)
log(x)

所以您发布的代码实际上是正确的。

sp.log(x,3) 相当于 log(x)/log(3)，其导数为 1/( x*log(3))，在 Sympy 中相当于 1/(x*ln(3))。