Register to reply

Area for slicing

by icystrike
Tags: slicing
Share this thread:
icystrike
#1
Mar15-11, 12:58 AM
P: 436
Can i ask what is the area we are refering to when we take such integral (r is the radius):

[tex]\int_{-\infty }^{\infty }e^{-r^{2}}dr[/tex]

I'm suspecting that its is the area of slices of bell curve that rotates about the z-axis.

Attached Thumbnails
graph.png  
Phys.Org News Partner Science news on Phys.org
'Smart material' chin strap harvests energy from chewing
King Richard III died painfully on battlefield
Capturing ancient Maya sites from both a rat's and a 'bat's eye view'
tiny-tim
#2
Mar15-11, 06:07 AM
Sci Advisor
HW Helper
Thanks
tiny-tim's Avatar
P: 26,148
hi icystrike!

it's the integral of a vertical slice of the bell curve through its centre
HallsofIvy
#3
Mar15-11, 06:11 AM
Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,682
You understand, I hope, that finding area is one possible application of the integral. When we calculate an integral we are not necessarily finding any area at all!

icystrike
#4
Mar15-11, 01:42 PM
P: 436
Area for slicing

Thanks tiny-tim and HallsofIvy!

Yes! I know that! We can use Integral to compute things like work, flux, centroids .. =D

Its just that my teacher actually relate the slice as "some slice that is parallel to the y-axis" while i think that it should be the slice that is passing through origin(He've probably made some mistake)... (My teacher was actually comparing the volume of a rotated bell curve about z axis by slice and shells to evaluate the area under bell curve - [tex]A^{2}=\pi[/tex] )
tiny-tim
#5
Mar15-11, 01:47 PM
Sci Advisor
HW Helper
Thanks
tiny-tim's Avatar
P: 26,148
hi icystrike!
Quote Quote by icystrike View Post
Its just that my teacher actually relate the slice as "some slice that is parallel to the y-axis" while i think that it should be the slice that is passing through origin
i think he means that it'll be the same (it's the same shape), apart from a factor e-x2
icystrike
#6
Mar15-11, 02:14 PM
P: 436
Oh! Thats what he meant! Truly enlighten! Thanks Tim! :)
(Came to ensure that i get the concept right)


Register to reply

Related Discussions
Vectors help - Slicing Corner problem Precalculus Mathematics Homework 33
Density, Volume and Slicing Problem Calculus & Beyond Homework 2
Volumes by Slicing and Rotation About an Axis Calculus & Beyond Homework 4
Slicing dice and cutting corners General Math 2
Help with Volumes by slicing Calculus 11