using brent method iter [ lower, upper] min err err(est) 0 [0.0000000, 6.0000000] 2.0000000 -1.1415927 6.0000000 1 [2.0000000, 6.0000000] 3.5278640 +0.3862713 4.0000000 2 [2.0000000, 3.5278640] 3.1748217 +0.0332290 1.5278640 3 [2.0000000, 3.1748217] 3.1264576 -0.0151351 1.1748217 4 [3.1264576, 3.1748217] 3.1414743 -0.0001183 0.0483641 5 [3.1414743, 3.1748217] 3.1415930 +0.0000004 0.0333474 Converged: 6 [3.1414743, 3.1415930] 3.1415927 +0.0000000 0.0001187