3.3.4. Area Calculation in Rectangular Coordinates

Let two functions y = f ( x ) and y = φ ( x ) be continuous on the interval [ a, b ] , with f ( x ) ≥ φ ( x ) for all (Fig. 14). The area S of the figure bounded by the lines y = f ( x ) , y = φ ( x ) and the straight lines x = a, x = b , is found by the formula: .

Fig. 14