... haveQ1P1R1Q1=Q1p1r1Q1,Q2P2R2Q2=Q2p2r2Q2,Q3P3R3Q3=Q3p3r3Q3, etc.,but the denominators of the fractions on the right hand of the equations areall of them, by hypothesis, unity. Therefore the steepness of the curve at the points P1, P2, ... than i ALPHABET OF ECONOMIC SCIENCE 26Now since the increase of the function is represented by the rising of the curve, the rate at which the function is increasing is the same thing as the rate ... ALPHABET OF ECONOMIC SCIENCE BY PHILIP H. WICKSTEED ELEMENTS OF THE THEORY OF VALUE OR WORTH i ALPHABET OF ECONOMIC SCIENCE 32rate will be half way between y1and y2. This is represented by the line AB,which...