变量未定义，我不知道如何定义它

Question

Vsub=V.subs(-(2 - x**4)**(3/2)/6,0)
print('The volume when x=0 is',Vsub)

Name error: name 'V' is not defined 

Answer 1

在isympy会话中，

In [114]: V = sympify('-(2-x**4)**(3/2)')                                                            

In [115]: V                                                                                          
Out[115]: 
         3/2
 ⎛     4⎞   
-⎝2 - x ⎠   

In [116]: V.subs({x:0})                                                                              
Out[116]: -2⋅√2