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How was 9709_w15_qp_22

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Anyways this was a messed up paper bro. I used to get 90's straight. After this I'll even settle for a 80
 
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Bro I think ur differentiation is wrong. U got to multiply it by -4x which is the differentiation of the inside terms
 
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Could u do that thing of showing B is a midpoit of OP ?
How did u do?
We had y = (9 - 2x^2)^1/2 and point was (2,1) can u show me how did u do? Coz m getting 2y =x :(

You're making me relive a nightmare :cry:

You had to show that AP's midpoint was B. AP was a normal to the curve.
Differentiate y = (9 - 2x^2)^1/2, then substitute x for 2. That's your gradient of the curve. Then use m1m2 = -1 to find the normal's gradient. Once you do that,
use y-y1=m(x-x1) to find the equation of the normal. Once you get that, substitute y for 0 (since A lies on the x axis). You'll get the coordinates of A. Then, substitute x for 0 (since y lies on the y axis). You'll get the coordinates of B. Next, find the coordinates of the midpoint of AP, which is the same as B's coordinates.
 
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You're making me relive a nightmare :cry:

You had to show that AP's midpoint was B. AP was a normal to the curve
Differentiate y = (9 - 2x^2)^1/2, then substitute x for 2. That's your gradient of the curve. Then use m1m2 = -1 to find the normal's gradient. Once you do that,
use y-y1=m(x-x1) to find the equation of the normal. Once you get that, substitute y for 0 (since A lies on the x axis). You'll get the coordinates of A. Then, substitute x for 0 (since y lies on the y axis). You'll get the coordinates of B. Next, find the coordinates of the midpoint of AP, which is the same as B's coordinates.
Chill bro, we will get the thing we deserve. :)
Thanks.
 
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Yes. Make x the subject of the equation, then use the volume of revolution equation, only this time, you have to integrate x with respect to y.
 
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Yeah I got that. Sorry was talking about the volume of the wedge thing. Where they poured water !!
 
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