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Integration Constant

THEOREM 3

Suppose the domain off is an open interval I and f has an antiderivative. Let P(x0, y0) be any point with x0 in I. Then f has exactly one antiderivative whose graph passes through P.

PROOF

Let F be any antiderivative of f Then F(x) + C is the family of all anti derivatives. We show that there is exactly one value of C such that the function F(x) + C passes through P(xo,yo) (Figure 4.3.2). We note that all of the following statements are equivalent:

(1)    F(x) + C passes through P(x0,y0).

(2)    F(x0) + C = y0.

(3)     C = y0 = F(x0).

Thus y0 - F(x0) is the unique value of C which works.

04_integration-193.gif

Figure 4.3.2

The Fundamental Theorem of Calculus, part (ii), may be expressed briefly as follows, wheref is continuous on I. If f(x)dx = F(x) + C,then

04_integration-194.gif

For evaluating definite integrals we introduce the convenient notation

04_integration-195.gif

It is read "F(x) evaluated from a to b."

The Constant and Sum Rules hold for definite as well as indefinite integrals:

Constant Rule

04_integration-196.gif

Sum Rule

04_integration-197.gif

The Constant Rule is shown by the computation

04_integration-201.gif

The Sum Rule is similar.

Power Function

Integral of a Trigonometric Function

Hyperbolic Function

Integral of Discontinuous Functions


Last Update: 2006-12-01