Math Help Forum

Math Help Forum Feed Site Feed

Go Back   Math Help Forum > University Math Help > Calculus
Reply
 
Thread Tools Display Modes
  #1  
Old October 9th, 2006, 11:51 PM
Member
 
Join Date: Sep 2005
Posts: 136
Thanks: 16
Thanked 0 Times in 0 Posts
bobby77 is on a distinguished road
Default curve sketching

let f(x)= ((3x-1)|x-1|) / (x-1) for x !=0
(a) sketch the graph of f(x)
(b)evaluate lim x->1+ f(x)
(c) evaluate lim x->1- f(x)
(d)evaluate lim x->1 f(x)
Reply With Quote
Advertisement
 
  #2  
Old October 10th, 2006, 05:32 AM
CaptainBlack's Avatar
Grand Panjandrum
 
Join Date: Nov 2005
Location: South of England
Posts: 12,281
Country:
Thanks: 779
Thanked 4,004 Times in 3,229 Posts
CaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond reputeCaptainBlack has a reputation beyond repute
Default

Quote:
Originally Posted by bobby77 View Post
let f(x)= ((3x-1)|x-1|) / (x-1) for x !=0
(a) sketch the graph of f(x)
This behaves linearly in x except when x=1, where there is a jump discontinuity. This is because |x-1|/(x-1) is a constant equal to +1
when x>1, and a constant equal to -1 when x<1.


For x>1 we have:

f(x) = 3x-1

and for x<1, we have:

f(x) = -3x+1,

with a jump discontiuity where f changes grom -2 to the left of x=1
to ~2 to the right of x=1.

Now I have a sketch of this but the upload function appears to be
brocken

Quote:
(b)evaluate lim x->1+ f(x)
If the diagram had uploaded it would be clear that the limit as x goes to
1 from above is the limit as x goes to 1 of 3x-1 which is equal to 2.

Quote:
(c) evaluate lim x->1- f(x)
If the diagram had uploaded it would also be clear that the limit as x goes to
1 from below is the limit as x goes to 1 of -3x+1 which is equal to -2.

Quote:
(d)evaluate lim x->1 f(x)
As the two previous limits are not equal there is no such limit.

RonL
__________________
Truth does not change because it is, or is not, believed by a majority of the people.

Giordano Bruno

Last edited by CaptainBlack; October 10th, 2006 at 07:29 AM.
Reply With Quote
  #3  
Old October 10th, 2006, 11:09 AM
earboth's Avatar
Super Member

 
Join Date: Jan 2006
Location: Germany
Posts: 4,586
Country:
Thanks: 190
Thanked 2,014 Times in 1,845 Posts
earboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond repute
Default

Quote:
Originally Posted by bobby77 View Post
let f(x)= ((3x-1)|x-1|) / (x-1) for x !=0
(a) sketch the graph of f(x)
...
Hi,

I'll try to upload the graph. It's working!

Then here is the graph of your function:
Attached Thumbnails
curve-sketching-fkt_sprung.gif  
Reply With Quote
Reply

« Convergence | Top | Mass »
Thread Tools
Display Modes

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off
Forum Jump


All times are GMT -7. The time now is 11:25 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2010, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.2.0 ©2008, Crawlability, Inc.
©2005 - 2009 Math Help Forum


Math Help Forum is a community of maths forums with an emphasis on maths help in all levels of mathematics.
Register to post your math questions or just hang out and try some of our math games or visit the arcade.