Replace the coefficient of abs in the lookup table of meijerint.

sympy/integrals/meijerint.py

@@ -108,7 +108,7 @@ def eval(cls, arg):
     add((b + t)**(-a), [1 - a], [], [0], [], t/b, b**(-a)/gamma(a),
         hint=Not(IsNonPositiveInteger(a)))
     add(abs(b - t)**(-a), [1 - a], [(1 - a)/2], [0], [(1 - a)/2], t/b,
-        pi/(gamma(a)*cos(pi*a/2))*abs(b)**(-a), re(a) < 1)
+        2*sin(pi*a/2)*gamma(1 - a)*abs(b)**(-a), re(a) < 1)
     add((t**a - b**a)/(t - b), [0, a], [], [0, a], [], t/b,
         b**(a - 1)*sin(a*pi)/pi)
 

sympy/integrals/tests/test_transforms.py

@@ -110,7 +110,8 @@ def test_mellin_transform():
 
     # TODO also the conditions should be simplified
     assert MT(abs(1 - x)**(-rho), x, s) == (
-        cos(pi*(rho/2 - s))*gamma(s)*gamma(rho - s)/(cos(pi*rho/2)*gamma(rho)),
+        2*sin(pi*rho/2)*gamma(1 - rho)*
+        cos(pi*(rho/2 - s))*gamma(s)*gamma(rho-s)/pi,
         (0, re(rho)), And(re(rho) - 1 < 0, re(rho) < 1))
     mt = MT((1 - x)**(beta - 1)*Heaviside(1 - x)
             + a*(x - 1)**(beta - 1)*Heaviside(x - 1), x, s)
@@ -126,6 +127,7 @@ def test_mellin_transform():
     assert MT(expr.subs(b, bpos), x, s) == \
         (-a*(2*bpos)**(a + 2*s)*gamma(s)*gamma(-a - 2*s)/gamma(-a - s + 1),
          (0, -re(a)/2), True)
+
     expr = (sqrt(x + b**2) + b)**a/sqrt(x + b**2)
     assert MT(expr.subs(b, bpos), x, s) == \
         (2**(a + 2*s)*bpos**(a + 2*s - 1)*gamma(s)