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] rationalizing the denominator
Replies: 2   Last Post: Aug 28, 2012 1:02 PM

 Messages: [ Previous | Next ]
 Carole Stevens Posts: 10 Registered: 5/17/12
Re: [ap-calculus] rationalizing the denominator
Posted: Aug 28, 2012 12:20 PM

In Calculus it is sometimes necessary to move a radical INTO the
denominator in order to determine a limit, so rationalizing all
denominators is pointless, IMO. In Precalculus, we begin explaining this
to students, and in AP Calculus, we point out that it is not necessary. On
the AP exam, any mathematically correct form of the answer is accepted, so
I actually encourage them to leave their answers in the form that they get,
radical in the bottom or not. Since some textbooks persist in
rationalizing the denominators, I just tell the students to check to see if
the solutions are equivalent by evaluating both on the calculator (just for
checking, not answering the question using a calculator).

HTH,
Carole

On Tue, Aug 28, 2012 at 7:19 AM, allison heyl <alheyl@yahoo.com> wrote:

>
> How do people feel about rationalizing the denominator? (especially unit
> circle). Some books are now leaving the radical in the denominator and I
> am not sure what to tell my students.
>
> Thanks
> Allison
>
>
> ====
> Course related websites: http://apcentral.collegeboard.com/calculusabhttp://apcentral.collegeboard.com/calculusbc
>
> To search the list archives for previous posts go to
>
> To unsubscribe use this URL: http://lyris.collegeboard.com/read/my_forums/
>
> To change your subscription address or other settings use this URL:
>

--

*Carole Stevens
*Monsignor Kelly Catholic High School<http://www.monsignorkellyhighschool.com/>
409-866-2351 ext 159
409-860-0874 fax
CStevens@MKCHS.com

====
Course related websites:
http://apcentral.collegeboard.com/calculusab
http://apcentral.collegeboard.com/calculusbc
---
To search the list archives for previous posts go to