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March 29, 2024, 03:07:53 am

Author Topic: Mathematics Question Thread  (Read 1296773 times)  Share 

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jakesilove

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Re: Mathematics Question Thread
« Reply #1215 on: February 20, 2017, 03:39:33 pm »
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Hey im trying to revise. Do you think you could help me out there with an explanation and working out of each of them? Thank you.

Hey!







By cancelling terms.

To find the slope of a tangent, we have to find the first derivative.



Dammit Rui
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RuiAce

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Re: Mathematics Question Thread
« Reply #1216 on: February 20, 2017, 03:53:32 pm »
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itswags98

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Re: Mathematics Question Thread
« Reply #1217 on: February 20, 2017, 05:25:27 pm »
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Dammit Rui

Thanks for your help guys :3 Especially Rui ahah
Goal of 85 ATAR. Lets do eht

Hplovers

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Re: Mathematics Question Thread
« Reply #1218 on: February 20, 2017, 05:47:01 pm »
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Please help!  :o

1. Find the area enclosed between the curve y=x^3 , the x-axis and the line y= -3x+4

Im not sure what my first equation should be... (not sure what is considered top or bottom curve, and I cant find the intersection point  :'( )

Thanks!

smile123

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Re: Mathematics Question Thread
« Reply #1219 on: February 20, 2017, 05:53:10 pm »
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please help

RuiAce

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Re: Mathematics Question Thread
« Reply #1220 on: February 20, 2017, 06:52:22 pm »
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Please help!  :o

1. Find the area enclosed between the curve y=x^3 , the x-axis and the line y= -3x+4

Im not sure what my first equation should be... (not sure what is considered top or bottom curve, and I cant find the intersection point  :'( )

Thanks!



please help


jamonwindeyer

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Re: Mathematics Question Thread
« Reply #1221 on: February 20, 2017, 09:07:54 pm »
+1
This never gets old 8)

We seriously need a dibs system :P

teapancakes08

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Re: Mathematics Question Thread
« Reply #1222 on: February 20, 2017, 09:49:24 pm »
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21. Find the volume of the solid of revolution formed if the area enclosed between the curves y = x^2 and y = (x - 2)^2 is rotated about the x-axis.

I've (sorta) drawn the graph but am stumped on finding the definite integrals. Should be fine with using the formula after that though. I think. Correct me if I'm wrong but would you use both the volume formula and the sums and differences of two areas (or volumes in this case)? Something like pi integral (x^2)^2 - pi integral ((x-2)^2)^2 (I have no idea what I'm doing, I'm sorry >.<)




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jamonwindeyer

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Re: Mathematics Question Thread
« Reply #1223 on: February 20, 2017, 09:51:21 pm »
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21. Find the volume of the solid of revolution formed if the area enclosed between the curves y = x^2 and y = (x - 2)^2 is rotated about the x-axis.

I've (sorta) drawn the graph but am stumped on finding the definite integrals. Should be fine with using the formula after that though. I think. Correct me if I'm wrong but would you use both the volume formula and the sums and differences of two areas (or volumes in this case)? Something like pi integral (x^2)^2 - pi integral ((x-2)^2)^2 (I have no idea what I'm doing, I'm sorry >.<)

Hey! Assuming they mean that little triangular looking region enclosed by the parabolas and the x-axis, just take the volume in two halves! One from 0 to 1 for \(y=x^2\), then the other for 1 to 2 for \(y=(x-2)^2\) ;D

Oh and never apologise for asking a question! Seriously all good, we are happy to help ;D

Hplovers

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Re: Mathematics Question Thread
« Reply #1224 on: February 20, 2017, 10:09:33 pm »
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Sorry i'm still confused
I'm not sure how to find the point of intersection; please explain (2 unit level) and the crossing over of the curves makes it hard for me to know which curve i'm subtracting from which (which is one the bottom).
When you tell me the intersection is x = 1 I can solve it fine, but I just don't know which one is top and which is bottom.
(attached graph)

Also there's another question that i've tried so many times but keep getting confused (probably just with my algebra).
Find the exact area enclosed between the curve y= sqrt(4-x^2) and the line x-y+2=0
I would really appreciate the working out. :)

Thankyou so so much for your help but please don't assume that I know as much as you do, it's not obvious to me, otherwise I wouldn't have asked for the help; i've tried the questions many many time but I keep doing something wrong.
Thankyou :)

RuiAce

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Re: Mathematics Question Thread
« Reply #1225 on: February 20, 2017, 10:16:40 pm »
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Sorry i'm still confused
I'm not sure how to find the point of intersection; please explain (2 unit level) and the crossing over of the curves makes it hard for me to know which curve i'm subtracting from which (which is one the bottom).
When you tell me the intersection is x = 1 I can solve it fine, but I just don't know which one is top and which is bottom.
(attached graph)

Also there's another question that i've tried so many times but keep getting confused (probably just with my algebra).
Find the exact area enclosed between the curve y= sqrt(4-x^2) and the line x-y+2=0
I would really appreciate the working out. :)

Thankyou so so much for your help but please don't assume that I know as much as you do, it's not obvious to me, otherwise I wouldn't have asked for the help; i've tried the questions many many time but I keep doing something wrong.
Thankyou :)







RuiAce

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Re: Mathematics Question Thread
« Reply #1226 on: February 20, 2017, 10:21:14 pm »
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bananna

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Re: Mathematics Question Thread
« Reply #1227 on: February 21, 2017, 06:23:30 am »
+1
No Part B looks okay in the version you posted! You've got:



That's correct! The 54/125 comes from Part A :)

awesome discussion on this q :) 
everyone's working out gave me a great outline, but I think I got it when my cousin helped me-he drew a tree diagram

thanks to all :)

jamonwindeyer

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Re: Mathematics Question Thread
« Reply #1228 on: February 21, 2017, 10:23:07 am »
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awesome discussion on this q :) 
everyone's working out gave me a great outline, but I think I got it when my cousin helped me-he drew a tree diagram

thanks to all :)

Awesome! Tree diagrams are almost always the saviour ;)

smile123

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Re: Mathematics Question Thread
« Reply #1229 on: February 21, 2017, 12:24:16 pm »
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please help