... 1; 2; 3; 20 NUMBERS [CHAP. 1 Theory and Problems of ADVANCEDCALCULUS Second Edition ROBERT WREDE, Ph.D.MURRAY R. SPIEGEL, Ph.D.Former Professor and Chairman of MathematicsRensselaer Polytechnic ... a and b are any natural numbers. This leads to theoperation of subtraction,orinverse of addition,andwewrite x ¼ a À b.The set of positive and negative integers and zero is called the set of ... integral of f ðxÞ between a and b.Inthis symbol f ðxÞdx is called the integrand, and ½a; b is called the range of integration.Wecalla and b the limits of integration, a being the lowerlimit of integration...