Hello again, how to compute f(x):=(500* ((0.0075+log((x/15.5)+1))^0.2)*x((5.5^2)-(x^2))^0.5-((4.5^2)-(x^2))^0.5); integrate(f(x), x, 0, 4.5); My Simpson-Algorithm in VBA and MuPad compute to 5203.13231... Hans W. Hofmann