ihatehippos101
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Looking for HSC notes and resources? Check out our Notes & Resources page
can someone explain pls ty (1 Viewer)
- Thread starter ihatehippos101
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coolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
these look like normanhurst boys papers.
those papers are fucking boring ugly and unrealistic i just dont do them
those papers are fucking boring ugly and unrealistic i just dont do them
coolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
who tf makes these questions, i don't even understand what it's asking for 
be rest assured that a question like this won't be asked in the hsc
be rest assured that a question like this won't be asked in the hsc
melanie_o
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It is 100% something NESA can ask in ext 1who tf makes these questions, i don't even understand what it's asking for
be rest assured that a question like this won't be asked in the hsc
coolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
not when it's worded like the bullcrap this is. this is so ambigious it's retarded
alphxreturns
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its asking this right?
coolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
i don't know why they couldnt've just shaded it. this is not fucking english,
i mean, why the fuck did you include a graph then?
these patronizing asshole math teachers piss me off
alphxreturns
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am i right or ?
my idea is having a cylinder with height 3π and radius 1, getting its volume, then subtracting the volume made by rotating around y axis, x=0 -> x=1 and y=0 -> y=3π/2
i dont see how it could be wrong because the volumes should be equivalent but chatgpt says its so wrong
it is 1am i guess i am tripping as heckcoolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
i think u are.
also the HSC always shows you a shaded graph for these types of questions.
alphxreturns
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hope it helps and hope its correct otherwise my aura is down the drain
coolcat6778
ICE Out, I Hate MAGAts, I hate Dump, F-ck Nazis
cylinders are suppose to be for extension 2 old syllabus
chillbrowassurproblem
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(9pi^2)/4
cheesynooby
٩(๑❛ᴗ❛๑)۶
why are u both on at 2amcylinders are suppose to be for extension 2 old syllabus
alphxreturns
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you should see our science papers...
This is not a cylindrical shells problem, @coolcat6778
As @alphxreturns has noted, the volume of the enclosing cylinder,
, is given by
where 
unit and 
units, giving
The part missing is
given by
} \\ &= \pi\int_{\frac{3\pi}{2}}^{3\pi} \cos^2{\left(\frac{y}{3}\right)}\,dy \\ &= \frac{\pi}{2}\int_{\frac{3\pi}{2}}^{3\pi} \cos{\left(\frac{2y}{3}\right)} + 1\,dy \qquad \text{using $\cos{2\alpha} = 2\cos^2\alpha - 1$ with $\alpha = \frac{y}{3}$} \\ &= \frac{\pi}{2}\left[\frac{3}{2}\sin{\left(\frac{2y}{3}\right)} + y\right]_{\frac{3\pi}{2}}^{3\pi} \\ &= \frac{\pi}{2}\left[\left(\frac{3}{2}\sin{2\pi} + 3\pi\right)-\left(\frac{3}{2}\sin{\pi} + \frac{3\pi}{2}\right)\right] \\ &= \frac{\pi}{2}\left[\left(\frac{3}{2}\times 0 + 3\pi\right)-\left(\frac{3}{2}\times 0 + \frac{3\pi}{2}\right)\right] \\ &= \frac{\pi}{2} \times \frac{3\pi}{2} \\ &= \frac{3\pi^2}{4}\ \text{cu. units} \end{align*})
Hence, the required volume is
Matching the two correct answers already given
As @alphxreturns has noted, the volume of the enclosing cylinder,
The part missing is
Hence, the required volume is
Matching the two correct answers already given