Higher Maths Paper 1

Maybe_Memories

^^^ Easier than my substitution method, but both are still valid

Maybe_Memories

Digits wrote: »

Thanks:)

Actually, man, forget the substitution way. Follow Michael E's way. My way gets too complicated when I actually did it out.

Sorry for the confusion

River Song

I would do it the x=rsinA method for sure. That's just me though.

PJelly

Michael_E wrote: »

I would do it the x=rsinA method for sure. That's just me though.

Wait, are we still trying to get the roots of a cubic here?
I've never seen the "X=rsinA" medhod in my life.
I just plug in figures till one equals zero. Take that as my factor, long divide, get my quadratic and solve that for the other two.

Maybe_Memories

Michael_E wrote: »

I would do it the x=rsinA method for sure. That's just me though.

I like your style

Anyone intending on doing maths or physics in college, be VERY comfortable with paper 1 stuff.

River Song

PJelly wrote: »

Wait, are we still trying to get the roots of a cubic here?
I've never seen the "X=rsinA" medhod in my life.
I just plug in figures till one equals zero. Take that as my factor, long divide, get my quadratic and solve that for the other two.

I was referring to the deriving a formula for the area of a circle, by intergration methods.

I find the roots of a cubic the same way as you

Maybe_Memories wrote: »

I like your style

Anyone intending on doing maths or physics in college, be VERY comfortable with paper 1 stuff.

GRAND OUT Science Ed. in DCU as my #1, then Pure Maths in Trinners, MPS in UCD, etc etc :P

Maybe_Memories

PJelly wrote: »

Wait, are we still trying to get the roots of a cubic here?
I've never seen the "X=rsinA" medhod in my life.
I just plug in figures till one equals zero. Take that as my factor, long divide, get my quadratic and solve that for the other two.

We stopped talking about cubics ages ago

Yeah, you're way is right, we're on about integrating circles here

Digits

Maybe_Memories wrote: »

Actually, man, forget the substitution way. Follow Michael E's way. My way gets too complicated when I actually did it out.

Sorry for the confusion

But his was for volume, im looking for area.

Michael would you be able to give a brief overview of it. I keep trying the substitution but its not working out.

PJelly

Michael_E wrote: »

I was referring to the deriving a formula for the area of a circle, by intergration methods.

I find the roots of a cubic the same way as you

Oh right! You had me worried!
the circle is to integrate r^2 - X^2 from -r to r right?
And don't forget your pi!
(My teacher always says :rolleyes:)

Maybe_Memories

IF YOU DO THE X=RSINA METHOD DO NOT FORGET TO MULTIPLY BY 2 AT THE END, OTHERWISE YOU GET THE VOLUME OF A SEMI-CIRCLE

River Song

Maybe_Memories wrote: »

IF YOU DO THE X=RSINA METHOD DO NOT FORGET TO MULTIPLY BY 2 AT THE END, OTHERWISE YOU GET THE VOLUME OF A SEMI-CIRCLE

I just wrote that point down in red pen on the sheet I'm doing that proof on atm :P

People, Text and Tests 5, go to page 90 and do question 25.

PJelly

Oh a circle not a sphere!
Those are the lovely integrals with the million steps aren't they?
A nice part c
X= aSinr, change limits, sub in, get cos^2
blah blah blah

River Song

PJelly wrote: »

Oh a circle not a sphere!
Those are the lovely integrals with the million steps aren't they?
A nice part c
X= aSinr, change limits, sub in, get cos^2
blah blah blah

That's it exactly I would LOVE for that to come up! I always got such a kick out of doing them :P

Digits

FINALLY!!! Worked it out eventually. Thanks for the help lads.

Maybe_Memories

It's actually quite frightening how much I've forgotten since christmas...

PJelly

Michael_E wrote: »

I just wrote that point down in red pen on the sheet I'm doing that proof on atm :P

People, Text and Tests 5, go to page 90 and do question 25.

Soo.. I'm at the stage where I have to integrate 25Cos^2X.... that sound right?
Doesn't seem to be working out

PJelly

Im integrating root 25-X^2 from -5 to 5...
I hope I'm going about this the right way

River Song

PJelly wrote: »

Soo.. I'm at the stage where I have to integrate 25Cos^2X.... that sound right?
Doesn't seem to be working out

You can take 25 outside the intergral sign and make sure you've changed the limits!

Donerkebab

Michael_E wrote: »

Okay here are the proofs of the sphere/cone volume. I figured out the area one, but it's on my whiteboard and not on paper, sorry :P

Sphere


Cone

The last line of your circle on is incorrect i think. It should be 2r^3-2r^3/3

PJelly

Michael_E wrote: »

You can take 25 outside the intergral sign and make sure you've changed the limits!

Got it.
I did it the big stupid way you do them normally.
Ended up with loads of 25/4's, added em up, multiply by two and hey presto! 25pi.

River Song

Donerkebab wrote: »

The last line of your circle on is incorrect i think. It should be 2r^3-2r^3/3

That's the same thing. I just didn't group the r^3 with the other one, I manipulated them both into 2r^3/3 and added. It's the same thing.

River Song

PJelly wrote: »

Got it.
I did it the big stupid way you do them normally.
Ended up with loads of 25/4's, added em up, multiply by two and hey presto! 25pi.

Bang on

Maybe_Memories

Donerkebab wrote: »

The last line of your circle on is incorrect i think. It should be 2r^3-2r^3/3

He seems correct to me anyway.

Donerkebab

Michael_E wrote: »

That's the same thing. I just didn't group the r^3 with the other one, I manipulated them both into 2r^3/3 and added. It's the same thing.

Right

MikeHough

well lads. hope the studys goin well for ye.
I just finished correctin 2007 paper 1 there that i did today.
I'm presuming this is considered one of the easiest papers in past years cos i got 82%.It is, rite?????
either that or i have extremely surpassed myself!

Maybe_Memories

I don't remember 2007 off the top of my head, but 2010 was considered pretty easy if you knew your stuff to a decent level.

Although to be honest no year is really harder, some parts are just more tricky, but as a consequence there will be easier parts.


ADVICE:
You should all go get some sleep now
If you don't have geography, wake up early ish to get your mind into gear.
Don't stay up all night cramming...

(... no matter how much you love maths, cause we all love maths here, right??! )


:L :L :L

River Song

Maybe_Memories wrote: »

I don't remember 2007 off the top of my head, but 2010 was considered pretty easy if you knew your stuff to a decent level.

Although to be honest no year is really harder, some parts are just more tricky, but as a consequence there will be easier parts.


ADVICE:
You should all go get some sleep now
If you don't have geography, wake up early ish to get your mind into gear.
Don't stay up all night cramming...

(... no matter how much you love maths, cause we all love maths here, right??! )


:L :L :L

I certainly love it. Plan to do the maths revision during the geog exam, they're letting me use a room in school I'm gonna warm up with some sudokus, then do revision, then lunch and do sudoku before I go in

Been nice doing maths with ye tonight, all the best tomorrow

Donerkebab

Maybe_Memories wrote: »

(... no matter how much you love maths, cause we all love maths here, right??! )


:L :L :L

Of course, its a lovely subject! Quite looking forward to it for some strange reason!

Maybe_Memories

If you really like it then I strongly suggest doing maths in college.

It gets extremely interesting.

PJelly

Eek! Can't find a mathamatical set! Are they really that vital?