# Current Year 12 Thread Mark I (2012-2013)Watch

This discussion is closed.
6 years ago
#7521
(Original post by Abject Testament)
Same
Did you do IGCSEs as well?
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6 years ago
#7522
Mixture of IGCSEs and normal gcses
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6 years ago
#7523
Just in awe, can you check this, volume of revolution, of y = x + 3/Rootx between 1 and 4.

Spoiler:
Show

y = x + 3/Rootx between 1 and 4.

Pi *integral* y^2 dx
Pi *integral* (x^2 + 6x/Rootx + 9/x) dx
Pi *integral* (x^2 + 6x(x^-1/2) + 9(x^-1)) dx

Pi *intergral* x^2 + *integral* 6x^(1/2) + *integral* 9/x

Pi [x^3/3 + 4x^(3/2) + 9ln|x|]

Excuse lack of latex...

Is that right so far?

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0
6 years ago
#7524
(Original post by L'Evil Fish)
Just in awe, can you check this, volume of revolution, of y = x + 3/Rootx between 1 and 4.

y = x + 3/Rootx between 1 and 4.

Pi *integral* y^2 dx
Pi *integral* (x^2 + 6x/Rootx + 9/x) dx
Pi *integral* (x^2 + 6x(x^-1/2) + 9(x^-1)) dx
Pi [x^3/3 + 3/Rootx -9/x^2]
Pi [(64/3 + 3/2 - 9/16)-(1/3 + 3 - 9)]
Pi (1053/48+ 272/48)
Pi (1325/48)
1325Pi/48

Excuse lack of latex...

Is that right so far?

My Username is really Poisson Distribution
Not quite sure how you got this... think you integrated it wrong.
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6 years ago
#7525
(Original post by justinawe)
Not quite sure how you got this... think you integrated it wrong.

I differentiated the second bits randomly xD

Re check the edit?

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0
6 years ago
#7526
(Original post by L'Evil Fish)

I differentiated the second bits randomly xF

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Think it should be
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6 years ago
#7527
(Original post by justinawe)

Think it should be
Yeah I have that now! (in the edit)

My Username is really Poisson Distribution
0
6 years ago
#7528
(Original post by L'Evil Fish)
Yeah I have that now! (in the edit)

My Username is really Poisson Distribution
0
6 years ago
#7529
(Original post by justinawe)
sorry
Okay, how do I latex fractions...

Do I have to type in, frac?
And how about Integral sign? And limits?

My Username is really Poisson Distribution
0
6 years ago
#7530
Spoiler:
Show

Oh I give up with latex...

(3x+1) + (1/2)e^2x - *integrate* (1/2)e^2x + 3 dx

Numbers in wrong?

Lol, made that up, did that come up in latex!?

My Username is really Poisson Distribution
0
6 years ago
#7531
All I can see is maths I don't understand.
What module is all this?
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#7532
(Original post by Deziah)
All I can see is maths I don't understand.
What module is all this?
Volumes of revolution is C4 if you're with Edexcel (not sure about other exam boards though).
6 years ago
#7533
(Original post by usycool1)
Volumes of revolution is C4 if you're with Edexcel (not sure about other exam boards though).
I need Latex tutorials lol, it's C4 with me as well

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0
6 years ago
#7534
(Original post by Deziah)
All I can see is maths I don't understand.
What module is all this?
No idea, I believe it's C4 ( From what Usycool said )....This looks hard...

Spoiler:
Show
Where did you get Pi from y = x + 3/Rootx between 1 and 4. :O
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6 years ago
#7535
(Original post by Sheel1)
No idea, I believe it's C4 ( From what Usycool said )....This looks hard...
When you learn it, it'll be fine

Integration (simple start, is opposite of differentiation) so you add one to the power and divide the co efficient by it.

If you differentiate 3x^2 + 4x + 1 you'd get 6x + 4.

If you integrate 6x + 4. You'd get 3x^2 + 4x + c (because c could be any number, we don't know it's 1)

Think of it as anti differentiation, and you can use it to find area under a graph, volume of 3D shapes

My Username is really Poisson Distribution
0
6 years ago
#7536
(Original post by Sheel1)
No idea, I believe it's C4 ( From what Usycool said )....This looks hard...

Spoiler:
Show
Where did you get Pi from y = x + 3/Rootx between 1 and 4. :O
It's a rule
To find the volume generated by a graph being rotated 360 degrees. You integrate the graph squared and multiply it by Pi

Eg y = x spin it around 360 degrees, what's the.volume between 1 and 2.

square y and you get x^2 right? So integrate that and do things (you'll learn soon) and multiply by pi!

My Username is really Poisson Distribution
0
#7537
(Original post by Sheel1)
No idea, I believe it's C4 ( From what Usycool said )....This looks hard...

Spoiler:
Show
Where did you get Pi from y = x + 3/Rootx between 1 and 4. :O
Have you done C2 yet? If not, it'll be hard to explain where the pi comes from.

(Original post by L'Evil Fish)
I need Latex tutorials lol, it's C4 with me as well

My Username is really Poisson Distribution
This is quite useful: http://www.thestudentroom.co.uk/wiki/LaTex
6 years ago
#7538
(Original post by L'Evil Fish)
Spoiler:
Show

Oh I give up with latex...

(3x+1) + (1/2)e^2x - *integrate* (1/2)e^2x + 3 dx

Numbers in wrong?

Lol, made that up, did that come up in latex!?

My Username is really Poisson Distribution
Close it's \int, not /int

When I was first learning how to use it, I kept referring to the article on how to do stuff. Now it just comes naturally
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6 years ago
#7539
(Original post by justinawe)
Close it's \int, not /int

When I was first learning how to use it, I kept referring to the article on how to do stuff. Now it just comes naturally

trying my new skillz
My Username is really Poisson Distribution
0
6 years ago
#7540
(Original post by L'Evil Fish)

My Username is really Poisson Distribution
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