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pythonsympysymbolic-integration

Integrate with sympy


I would like to integrate the function :

$$ int_0^R sqrt(R^2 - x^2) dx $$

from sympy import *
x = symbols('x')
R = symbols('R', real = True, constant = True)
integrate(sqrt(R**2-x**2),(x,0,R))

But it solves me this one in complex domain. Is-it possible to force sympy to give me the result which is PI R^2 ?


Solution

  • If you declare both x and R to be positive then you can get a simpler result but it's pi R^2/4:

    In [4]: x, R = symbols('x, R', positive=True)                                                                                                                                                               
    
    In [5]: Integral(sqrt(R**2-x**2),(x,0,R)).doit()                                                                                                                                                            
    Out[5]: 
       2
    π⋅R 
    ────
     4