volume generated by 2 graphs (1 Viewer)

[Hikari Clover]

:wave: thx

 

[nitnit]

hi there!!

this is the first time actually ME helping someone on this forum! I'm just a normal 3U student.. one of those low low 3U people =P

So hopefully what i have done is correct!

• find the pt of intersection between the two graphs i.e. x=2 and x=-1 but since it is only the 1st quadrant, we take the limit of 2 to 0.
• use the volume rotated by the y axis formula with y=x+1 - y=x^2 - 1
• must you have to change to x^2 the subject so y+1=x^2 and (y-1)^2=x
• and if you work it out I got 1/1/3 pie..

is that correct?

hope that helps although i suck at explaining =P

good luck on wednesdaaaaaaaayyyyyy!

 

[aalex]

Good luck!!!!:wave:

 

[Starcraftmazter]

I disagree. Notice the question asks for the volume of the area in quadrant one, however nitnit, your answer includes the area between the two graphcs in quadrant 4, which must be subtracted.

For my answer, I got pi.

http://images.starcraftmazter.net/maths/q1.jpg

This is a prime example of why you should always draw an accurate graph and shaded area/volume.

 

[Hikari Clover]

回复: Re: volume generated by 2 graphs

what aalex got is correct.......

probably