Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: [ap-calculus] Re: Integral Problem - Finney DeMana #59, p. 575
Replies: 1   Last Post: Apr 5, 2005 9:52 AM

 Richard J Maher Posts: 80 Registered: 12/6/04
[ap-calculus] Re: Integral Problem - Finney DeMana #59, p. 575
Posted: Apr 5, 2005 9:52 AM

Hello George,

The answers are the same, since they differ by a constant. Remember

(1/2)tan^2 u = (1/2)sec^2 u - 1/2.

Hope this helps.

Dick Maher

Richard J. Maher
Mathematics and Statistics
Loyola University Chicago
6525 N. Sheridan Rd.
Chicago, Illinois 60626
1-773-508-3565
rjm@math.luc.edu

On Mon, 4 Apr 2005, George Becker wrote:

This problem asks for the integral of sin(x-3)/cos^3(x-3)dx. Using
substitution with u=cosx yields 1/(2cos^2(x-3))+ C which is the answer
the book provides. Alternatively, this could be written as 1/2(sec^2(x-3)).

Question is when you change the original integral to
tan(x-3)sec^2(x-3)dx
and then integrate by substitution with u=tanx, you get 1/2(tan^2(x-3))+ C
which does not appear to be the same answer, even using common trig
identities.

Why does these two answers not agree?

George Becker
Pope John HS
Sparta, NJ

------------------------------------------------------------------------
You are subscribed to ap-calculus as: box-ap-calculus@mathforum.org

To unsubscribe send a blank email to
leave-ap-calculus@lyris.collegeboard.com

To update your preferences, search the archives or post messages online, visit http://lyris.collegeboard.com/cgi-bin/lyris.pl?site=collegeboard&enter=ap-calculus

If you need help using Lyris web interface go to:
http://www.lyris.com/lm_help/4.0/WebInterfaceforUsers.html

Visit AP Central(tm) - The online resource for teachers, schools, colleges, and education professionals-- http://apcentral.collegeboard.com

The College Board
45 Columbus Avenue
New York, NY 10023-6992