| Author |
Message |
![[Post New]](/templates/default/images/icon_minipost_new.gif) 29 May 2007 15:19:33 IST
|
|
|
guys, this is a sum from arihant diff.calculus and its been driving me crazy.its on page 472 of the book, if any of u have it...
if the function x3-9x2+24x+c has three real and distict roots alpha, beta and gamma then value of
[alpha ]+[beta]+[gamma] equals....
the answer is 7,8
of course, the book does have the soln. the problem is that i just dont understand it! reply asap
|
|
|
|
29 May 2007 15:40:31 IST
|
|
|
alpha+beta +gamma=9
or, [alpha]+[beta]+[gamma]+{alpha}+{beta}+{gamma}=9
now as the sum of greatest integer functions has to be an integer .............therefore the sum of fractional parts of alpha,beta,gamma also hav ta be an integer ...........the sum of fracional parts hav to be either 1 or 2 (cant be three as fractional prts are + ve non integers <1)........hence sum of integral parts have ta be 7 or 8........
|
this reply: 10 points
(with 2 
in 2 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
29 May 2007 17:02:03 IST
|
|
|
id like an alternative method please
|
this reply: 0 points
(with 0
in 0 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
2 Jun 2007 10:53:13 IST
|
|
|
BUT I THINK SID'S APROACH IS PRFECTLY CORRECT
|
Krishna Gopal Singh
B.Tech Chemical Engg
IIT Delhi 2002
Currently doing PhD from IIT Delhi |
this reply: 0 points
(with 0
in 0 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
|
|
Moderation Team
![[Up]](/templates/default/images/icon_up.gif "[Up]"){kind=icon}
2
