#4807 jacobi_p falls outside interval

[Dan Gildea]

(%i32) n:9,a:0,b:3,x:-5/6;
(%o32)                                 9
(%i33)  orthopoly_returns_intervals : true;
(%o33)                               true
(%i34) exact : float(jacobi_p(n,a,b,x));
(%o34)                        0.5660762409911204
(%i35) approx : jacobi_p(n,float(a),float(b),float(x));
(%o35)       interval(0.5660762409910873, 3.1780473026681246e-14)
(%i36) abs(exact - part(approx, 1)) <= part(approx, 2);
(%o36)         3.3084646133829665e-14 <= 3.1780473026681246e-14