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 Subject: Calculus-A Definite Integral Problem Category: Reference, Education and News > Homework Help Asked by: jktallnyc-ga List Price: \$2.50 Posted: 11 Dec 2005 12:06 PST Expires: 11 Dec 2005 16:52 PST Question ID: 604443
 ```Hi. This one is really killing me for some strange reason: Evaluate the following integral: 2 S[-x^2-2x]dx -3 *Note* Pretend S is the integral sign and pretend [] is the absolute value sign. Thanks for the help.```
 There is no answer at this time.

 ```Recall that the definition of |x| is x if x>0 and -x if x<0. You need to find the values of x such that -x^2 - 2x > 0 and -x^2 - 2x < 0, then do a separate integral for each of these.```
 ```So I found the values of x to be -2 and 0. So I separated the problem into three integrals. I ultimately got the answer to be 40/3. But my answer manual says the answer is 28/3, though sometimes my manual has errors. Which one is right this time? My answer or the manual's? Ugghhhhh, I don't know why I'm so tripped over this one in particular...```
 ```I got 28/3. For the integral from -3 to -2, I got 4/3, from -2 to 0 I got 4/3, and from 0 to 2 I got 20/3.```
 `Yay. I finally got it. Thanks for the help.`