Question 7 (1 Viewer)

NightShadow

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I'm just wondering..what value of theta did you get for hte largest value of the area?

was it pi/2 cause thats obviously not the answer...
 

NightShadow

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well consider the diagram again with 2theta.. that would give the angle of pi..

so.ermm..max area occurs when the gutter is a straight line?
 

CheekyPunk

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if its pi, then the area would be half a circle, which makes sense as the largest area - i think.
 

NightShadow

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ahh yes that makes sense haha silly me.. trying to sink my own boat haha

it makes sense cause co theta equals to zero so all the area is due to the sector of the shape
 

Sober

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I believe it was pi/2, remember, w is the only constant here, not r.
 

CheekyPunk

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NightShadow said:
ahh yes that makes sense haha silly me.. trying to sink my own boat haha

it makes sense cause co theta equals to zero so all the area is due to the sector of the shape
Ahh, dw, its always little things like that, that dont make sense in the pressure of the exam.
Annoying, but nothing much we can do.
 

Riviet

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Yeah, I also got pi/2. You can get it from the trig equation or by inspection of the diagram of various angles of theta.
 

NightShadow

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haha no no i wrote pi/2 in the exam and everything.. it was afterwards that i was like..wait a sec.. haha..lucky that
 

ali777

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i got pi/2 for the value of theta, and for the area in terms of w i think i got w^2/2pi but im not sure.
 

silentprayer

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yes its pi/2 but i put pi/4 because instead of cosO(sinO - OcosO) = 0 i wrote cosO(sinO - cosO) = 0 ....

so if i got pi/4 would i get marks for the next question if i used pi/4?
 

poopoohead

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ha ha for the last question i wrote: if theta = pi/2 and then did the working i think. or something like that. thats the biggest fluke ever. i just guessed it was pi/2. or maybe i wrote pi/4. who knows. but yeah, i think quite well on this question compared to the other questions.
 

Rax

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Yeah I actually found that question 7 the most straightforward of almost any paper, except I was about 3 steps off the answer for the derivitive in part ii) or b) or whatever it was.
Shame bout the rest of the paper

And yep pi/2 ftw ie cos(theta)=0 between 0 and pi
 

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