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[Rmd_1]

i don't know where i'm wrong at this quz? anybody can work out it for me , thanx

the curve y=2^x is rotated about the x-axis between x=1 and x=2 use simpson's rule with 3 function values to find an approximation of the volume of the solid formed, correct to 3 significant figures.

and the answer is 27.2unit^3

 

[~*HSC 4 life*~]

eh?
i've never used simpsons rule to find a volume
ahhh someone tell us how to do it! lol

 

[Rmd_1]

that's what i confused.

 

[Heinz]

its really the same thing. Just have to think about it for a lil bit.

 

[Rmd_1]

thanx man, u r genius ! ahh

so this quz can't solve by normal method , isn't it?

 

[Heinz]

Originally posted by Rmd_1

so this quz can't solve by normal method , isn't it?

There is a "normal" method but its pretty hard. Something about substituting 2^(2x) into e^(2xln(2)), then you gotta change the terminals, integrate the exponential blah blah. Too much thinking. I think the actual answer is 6pi/ln2

 

[Xayma]

They most probably wont ask you to do it via the normal method because they can test your normal integration with a quicker method that still tests it. Of course for a later question you might have to do it normally (unlikely)

 

[CM_Tutor]

Remember with this that Simpson's Rule is about estimate integrals, not areas. Thus, if you can express a volume as an integral, then you can estimate that integral via Simpson's Rule, and thus estimate the required volume.