The ebook Elementary Calculus is based on material originally written by H.J. Keisler. For more information please read the copyright pages.


Example 8

Find08_exp-log_functions-382.gif

Assume a > 0. We make the trigonometric substitution x = a sec 6, illustrated in Figure 8.7.1.

08_exp-log_functions-383.gif

Figure 8.7.1

Then

dx = a tan θ sec θ dθ, 08_exp-log_functions-384.gif

08_exp-log_functions-385.gif

Therefore

08_exp-log_functions-386.gif

The formula

08_exp-log_functions-387.gif

can be derived in a similar way and is left as an exercise.

The integrals

08_exp-log_functions-388.gif

can now be evaluated using integration by parts,

08_exp-log_functions-389.gif


Last Update: 2006-11-16