| Author |
Message |
![[Post New]](/templates/default/images/icon_minipost_new.gif) 24 Mar 2008 10:12:37 IST
|
|
|
Q.f:R R given by f(x)=x3+ax2+bx+c is a bijection iff? 1.a2>or equal to 3b 2.a2<or equal to 3b 3.a2=3b 4.none
|
|
|
|
|
|
|
|
it is 2.. a2<3b
the function is onto
to be one-one it should be monotonically increasing in its entire domain
use that condition
u will get 2
|
this reply: 5 points
(with 1 
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
24 Mar 2008 10:55:30 IST
|
|
|
A bijective function is one that is both one-one and onto. A one-ono function is always in increasing or decreasing in its domain.
The minimum value of the first term is 0 and occurs when  . Hence for the function to be one-one  .
 Hence B. edit: corrected mistake.
|
Guide to latex:
http://www.goiit.com/posts/list/community-shelf-a-guide-to-latex-48056.htm
|
this reply: 10 points
(with 2
in 2 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
24 Mar 2008 11:15:55 IST
|
|
|
the question says "iff" which means if and only if .
option B says "less than or equal to" . so B is the only correct option
|
this reply: 0 points
(with 0
in 0 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
24 Mar 2008 11:24:22 IST
|
|
|
yeah didnt see that it said "less than or equal to"
|
Guide to latex:
http://www.goiit.com/posts/list/community-shelf-a-guide-to-latex-48056.htm
|
this reply: 5 points
(with 1
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
|
|
Moderation Team
![[Up]](/templates/default/images/icon_up.gif "[Up]"){kind=icon}
