ntegrating w/ abs value?? (1 Viewer)

jkwii

Ultimate Member
Joined
Jan 4, 2007
Messages
216
Gender
Male
HSC
2008
I = S (2- |x|) dx from 3 to -3.. do u use the graph?? like area??
 

Js^-1

No tengo pantelonès
Joined
Oct 14, 2007
Messages
318
Gender
Male
HSC
2008
hmmm...No clue. Its not odd, so its not automatically zero. Maybe you have to integrate the parts seperately and add them? Like for x>0 and x<0? Integrating y=2-x from 0 to 3 and y=x-2 from -3 to 0. I have no idea if thats right or not, but thats how i'd try to do it.
 

conics2008

Active Member
Joined
Mar 26, 2008
Messages
1,228
Gender
Male
HSC
2005
use the fact that |x| = y=x and y = -x above the x axis
 

Templar

P vs NP
Joined
Aug 11, 2004
Messages
1,979
Gender
Male
HSC
2004
Break the integral into 2 and |x|, and use the fact |x| is even
 

conics2008

Active Member
Joined
Mar 26, 2008
Messages
1,228
Gender
Male
HSC
2005
Here I will list the steps for you

i) draw 2-|x|
ii) You will notice that its made up of two equations y=2-x and y=2+x
iii) you can do this by integration or by normal area rules because these shapes are triangles
iiii) use the normal triangles. I will post graph
 
Last edited:

jkwii

Ultimate Member
Joined
Jan 4, 2007
Messages
216
Gender
Male
HSC
2008
ok cool but integration with limits is not the same as finding areas. go figure.

J.
 

conics2008

Active Member
Joined
Mar 26, 2008
Messages
1,228
Gender
Male
HSC
2005
jkwii said:
ok cool but integration with limits is not the same as finding areas. go figure.

J.
Integration is the process of find the area between a curve.
 

Trebla

Administrator
Administrator
Joined
Feb 16, 2005
Messages
8,132
Gender
Male
HSC
2006
Using the definition:
| x | = x, if x ≥ 0
= - x, if x < 0

3-3(2 - |x|)dx = ∫30(2 - x)dx + ∫0-3(2 + x)dx

then integrate and evaluate...
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top