Author Topic: Maths & Physics Help  (Read 60927 times)

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #45 on: November 03, 2008, 11:54:02 am »
I can't use msn it conflixts with my operating system. Try yahoo or skype.

Offline badboy

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Re: Maths & Physics Help
« Reply #46 on: November 03, 2008, 01:20:23 pm »
yo star r pipol done with physics p3 n maths p2 because  i havnt done any of maths n physics i just did the practical p5 physics but the athas i dint do

Offline puppy

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Re: Maths & Physics Help
« Reply #47 on: November 03, 2008, 05:53:31 pm »
can sumone send me the marking schemes for maths paper 2 may/june 05 and 06?? please!!

Offline pixis

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Re: Maths & Physics Help
« Reply #48 on: November 03, 2008, 07:41:16 pm »
have you tried www.freeexampapers.com? I will check when I get home in a couple of hours.

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #49 on: November 03, 2008, 10:02:52 pm »
can sumone send me the marking schemes for maths paper 2 may/june 05 and 06?? please!!

here they are on www.freeexampapers.com

http://www.freeexampapers.com/Dndex.php?d=SUdDU0UvTWF0aHMvQ0lF&catagory=

Offline ---<--- StUdYiNg --->---

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Re: Maths & Physics Help
« Reply #50 on: November 04, 2008, 04:48:17 pm »
need help in math paper 2.hav it tmrw n m stuck in one qns.its frm may june 2008.number 10.can anyone help?? pls.....

Offline TravisMcDee

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Re: Maths & Physics Help
« Reply #51 on: November 04, 2008, 05:11:13 pm »
need help in math paper 2.hav it tmrw n m stuck in one qns.its frm may june 2008.number 10.can anyone help?? pls.....
(Volume factor)=(scale fator)^3
therefore = sqrt(216)=vol factor
=6

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #52 on: November 04, 2008, 05:14:07 pm »
Volume factor = length factor cubed
Therefore length factor = cube root of volume factor
Cube root of 216 is 6
therefore radius =3x6=18
height= 7x6=42
« Last Edit: November 04, 2008, 08:14:38 pm by astarmathsandphysics »

Offline qwerty

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Re: Maths & Physics Help
« Reply #53 on: November 04, 2008, 09:52:13 pm »
can someone help me with functions?
lol ,thanks!

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #54 on: November 04, 2008, 10:00:38 pm »
what do you want to know? Do you want questions answered?

Offline IGCSE Master

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Re: Maths & Physics Help
« Reply #55 on: November 04, 2008, 10:14:49 pm »
Functions:

f:x = 2x - 1   and   g:x = x²-1

Find:

f-¹(x)


gf(x)

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #56 on: November 04, 2008, 10:21:01 pm »
f=2x-1
Make x the subject
f+1 =2x so (f+1)/2=x
Now swap f and x
(x+1)/2=f
Now replace f by f^-1 to give (x+1)/2=f^-1

g(x)=x^2-1 so g(f)=f^2-1 but f(x)=2x-1
so g(f(x))=(2x-1)^2-1
                =(2x-1)(2x-1)-1
                =4x^2-2x-2x+1-1
                =4x^2-4x
             
« Last Edit: November 04, 2008, 10:25:02 pm by astarmathsandphysics »

Offline qwerty

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Re: Maths & Physics Help
« Reply #57 on: November 04, 2008, 10:27:22 pm »
thanks! i think i get it. so:

f(x) = 3 x - 1

f^-1(x) would then be:

f = 3x-1
f + 1 = 3x
f+1/3 = x
swap
x+1/3 = f
f^-1 = x+1/3

is that correct??

thanks a lot!!!

Offline astarmathsandphysics

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Re: Maths & Physics Help
« Reply #58 on: November 04, 2008, 10:29:10 pm »
should be (x+1)/3=f^-1(x)
x+1 has to be divided by 3 not just 1 divided by 3
« Last Edit: November 04, 2008, 10:32:18 pm by astarmathsandphysics »

Offline qwerty

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Re: Maths & Physics Help
« Reply #59 on: November 04, 2008, 10:34:20 pm »
oh i get it! thanks a lot!