Section 8.8 – Improper Integrals
The Fundamental Theorem of Calculus If f is continuous on the interval [ a,b ] and F is any function that satisfies F '(x) = f(x) throughout this interval then REMEMBER: [a,b] is a closed interval.
Improper Integral Areas of unbounded regions also arise in applications and are represented by improper integrals. Consider the following integral: Intuitively it appears any unbounded region should have infinite area.
Numerical Investigation b Numerically, it appears
Definition: The Integral Diverges
Improper Integral Areas of unbounded regions also arise in applications and are represented by improper integrals. Consider the following integral: Can the unbounded region have finite area?
Numerical Investigation b Numerically, it appears
Definition: The Integral Converges
“Horizontal” Improper Integrals Note: It can be shown the value of c above is unimportant. You can evaluate the integral with any choice. Both integrals must converge for the sum to converge.
Example 1
Improper Integral Technique The technique for evaluating an improper integral “properly” is to evaluate the integral on a bounded closed interval where the function is continuous and the Fundamental Theorem of Calculus applies, then take the offending end of the interval to the limit. On any free-response question, always use the limit notation to evaluate improper integrals. While the statement below may involve less writing, it is mathematically incorrect and will lose you points: DO NOT WRITE THIS!
Example 2 Use L'Hôpital's Rule
Example 2
White Board Challenge Evaluate:
The Fundamental Theorem of Calculus If f is continuous on the interval [ a,b ] and F is any function that satisfies F '(x) = f(x) throughout this interval then REMEMBER: f must be a continuous function.
Improper Integral Areas of unbounded regions also arise in applications and are represented by improper integrals. Consider the following integral: Can the unbounded region have finite area?
Numerical Investigation b Numerically, it appears
“Vertical” Improper Integrals Note: It can be shown the value of c above is unimportant. You can evaluate the integral with any choice. Both integrals must converge for the sum to converge.
Example 1
Example 2 Since the integral is infinite, it diverges (does not exist).
Example 3
White Board Challenge Evaluate: