The limit on the right in the starred equation is, by definition, the derivative of F(x), that is, f (x).
EXAMPLE 20
Reexpress in terms of u if
SOLUTION: When u^2 = x − 2, and 2u du = dx. The limits of the given integral are
values of x. When we write the new integral in terms of the variable u, then the limits, if written,
must be the values of u that correspond to the given limits. Thus, when x = 3, u = 1, and when x =
6, u = 2. Then
EXAMPLE 21
If g ′ is continuous, find
SOLUTION:
Note that the expanded limit is, by definition, the derivative of g(x) at c.
C. INTEGRALS INVOLVING PARAMETRICALLY DEFINED
FUNCTIONS
The techniques are illustrated in Examples 22 and 23.
BC ONLY
EXAMPLE 22
Evaluate where x = 2 sin θ and y = 2 cos θ.
SOLUTION: Note that dx = 2 cos θ dθ, that when x = −2, and that when x = 2.