Actuarial Outpost Integration question
 Register Blogs Wiki FAQ Calendar Search Today's Posts Mark Forums Read
 FlashChat Actuarial Discussion Preliminary Exams CAS/SOA Exams Cyberchat Around the World Suggestions

Search Actuarial Jobs by State @ DWSimpson.com:
AL AK AR AZ CA CO CT DE FL GA HI ID IL IN IA KS KY LA
ME MD MA MI MN MS MO MT NE NH NJ NM NY NV NC ND
OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY

 Probability Old Exam P Forum

#1
12-04-2017, 08:15 AM
 ch1rontl34 Member Join Date: May 2008 Posts: 141
Integration question

Hi everyone, I'm working on an MLC question but the question is actually calculus related. It's been many years since I passed P (career changer) and I can't seem to figure out this integration problem

I understand what u substitution is but I don't know how setting u=10-rootx leads to the 2 in the numerator. The steps in the attached picture are incomplete for my understanding, can anyone please help? Thank you!
Attached Images

Last edited by ch1rontl34; 12-04-2017 at 08:47 AM..
#2
12-04-2017, 08:34 AM
 Klaymen Member CAS Join Date: Oct 2001 Studying for 2018 Las Vegas NABC Posts: 19,194

Can't read the problem with a graphic that small. Try putting the image in paint and cropping out the important parts.
__________________

You make known to me the path of life; you will fill me with joy in your presence, with eternal pleasures at your right hand. (Psalm 16:11)
#3
12-04-2017, 08:35 AM
 Gandalf Site Supporter Site Supporter SOA Join Date: Nov 2001 Location: Middle Earth Posts: 30,913

Quote:
 Originally Posted by ch1rontl34 Hi everyone, I'm working on an MLC question but the question is actually calculus related. It's been many years since I passed P (career changer) and I can't seem to figure out this integration problem I understand what u substitution is but I don't know how setting u=10-rootx leads to the 2 in the numerator. The steps in the attached picture are incomplete for my understanding, can anyone please help? Thank you!
I can't see the picture clearly, but the 2 is probably associated with root x being x^(1/2) [and quite possibly then with the change of dx to du],
#4
12-04-2017, 08:48 AM
 ch1rontl34 Member Join Date: May 2008 Posts: 141

I have updated the attached file, sorry I didn't realize it showed up really small. I hope it's better now. Thanks to all who have responded already!
#5
12-04-2017, 09:01 AM
 Gandalf Site Supporter Site Supporter SOA Join Date: Nov 2001 Location: Middle Earth Posts: 30,913

Yes, what I expected. If

u = (10 - x^(1/2)) then

du/dx = -(1/2)x^(-1/2) so

du = -(1/2)[x^(-1/2)]dx

-2 du = [x^(-1/2)]dx

That last step is where the 2 comes from, also where the - in the numerator comes from.
#6
12-04-2017, 09:06 AM
 ch1rontl34 Member Join Date: May 2008 Posts: 141

I get it now, thanks Gandalf! I forgot about replacing dx in terms of du.

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off

All times are GMT -4. The time now is 09:21 AM.

 -- Default Style - Fluid Width ---- Default Style - Fixed Width ---- Old Default Style ---- Easy on the eyes ---- Smooth Darkness ---- Chestnut ---- Apple-ish Style ---- If Apples were blue ---- If Apples were green ---- If Apples were purple ---- Halloween 2007 ---- B&W ---- Halloween ---- AO Christmas Theme ---- Turkey Day Theme ---- AO 2007 beta ---- 4th Of July Contact Us - Actuarial Outpost - Archive - Privacy Statement - Top