MedVision ad

Area of integration, help plz (1 Viewer)

Joined
Mar 29, 2009
Messages
48
Gender
Male
HSC
2009
Calculate the area of the region bounded by:
y=1/x^2 + 2
y= -2x+5
x = 4


Answers were not given

Thanks in advance.
 
Joined
Mar 29, 2009
Messages
48
Gender
Male
HSC
2009












EDIT: Thought maybe i'd explain a few things. The reason you don't integrate straight between the point of intersection of the two curves (x=1) and the boundary x = 4 is because the area produced is not uniform. If you were to sketch the situation, you would see that from 1 to 5/2 (where the straight line cuts the x-axis) is one uniform area between the two curves. From 5/2 to 4 and the x-axis is uniform for the 1/x^2 + 2 graph so you only have to integrate that. Hope this makes sense.
mmm
But if you find the area of y=1/x^2+2. Isnt that = area in between the graph and y =2 ?

as y = 2 is an asymptote of y= 1/x^2+2
 

gurmies

Drover
Joined
Mar 20, 2008
Messages
1,209
Location
North Bondi
Gender
Male
HSC
2009
mmm
But if you find the area of y=1/x^2+2. Isnt that = area in between the graph and y =2 ?

as y = 2 is an asymptote of y= 1/x^2+2
Hmm, good point. I'm not too sure about this actually. On second thoughts, i'm quite sure you can't integrate over an asymptote.
 

shaon0

...
Joined
Mar 26, 2008
Messages
2,029
Location
Guess
Gender
Male
HSC
2009
Hmm, good point. I'm not too sure about this actually. On second thoughts, i'm quite sure you can't integrate over an asymptote.
I don't think you can't integrate over an asymptote as the area will be undefined at a point. But I maybe wrong entirely.
 
Last edited:

shaon0

...
Joined
Mar 26, 2008
Messages
2,029
Location
Guess
Gender
Male
HSC
2009
Can't say. At this point it remains trivial, although i'm leaning towards it not being able to be integrated. Then that means the question is void, does it not?

EDIT: Actually, maybe just integrate from the curve to y = 2 line and then add the rectangle below as it's a constituent of the whole area? Not sure..
You could take a limit as the function approaches the asymptote and integrate to infinity but that's too complicated and not necessary since gurmies has already got the solution. Should just wait for Trebla.
 
Last edited:
Joined
Mar 29, 2009
Messages
48
Gender
Male
HSC
2009
i showed u in class today lawrence...
You did, but i didnt accept it that day

but ye i do understand it and theres also another method for this but longer
.....im guessing your demanding a thanks from me lol?

thanks =p
 
Last edited:

Gibbatron

Member
Joined
Mar 20, 2009
Messages
339
Gender
Male
HSC
N/A
Drawing a diagram will always help because you can see what you have to integrate.
 

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

Top