我有以下代码片段
import sympy
a = sympy.symbols('a')
b = sympy.symbols('b')
c = sympy.symbols('c')
print((a*b).coeff(c,0))
print((a*b).as_independent(c)[0])
我不明白为什么两个print语句打印不同的输出。根据coeff的文件：
You can select terms independent of x by making n=0; in this case
expr.as_independent(x)[0] is returned (and 0 will be returned instead
of None):
>>> (3 + 2*x + 4*x**2).coeff(x, 0)
3
这是一个同情的错误，还是我错过了什么？