Author Topic: Additional Math Help HERE ONLY...!  (Read 68743 times)

Offline Dibss

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Re: Additional Math Help HERE ONLY...!
« Reply #270 on: June 03, 2010, 10:17:27 pm »
ok, let me go check the mark scheme and i'll get back to you!
it's from M/J 05 P2 =]

Offline astarmathsandphysics

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Re: Additional Math Help HERE ONLY...!
« Reply #271 on: June 04, 2010, 12:07:58 am »
My mistake - I read 165000 home which have both computer and dishwasher

Offline jellybeans

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Re: Additional Math Help HERE ONLY...!
« Reply #272 on: June 04, 2010, 03:15:04 am »
INCOMPLETE Q...post the paper link and ms..
ohh sry.

D: its incomplete?

answer to the venn diagram question

Check the attachment. Hope it helps =]

THANK YOU ;D ;D ;D !!
« Last Edit: June 04, 2010, 03:22:49 am by jellybeans »
You said I must eat so many lemons cause I am so bitter.

Offline jellybeans

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Re: Additional Math Help HERE ONLY...!
« Reply #273 on: June 05, 2010, 04:47:33 am »
HELLLLLLLP please ;)
thank you& its NOT an incomplete question :)
« Last Edit: June 05, 2010, 04:53:03 am by jellybeans »
You said I must eat so many lemons cause I am so bitter.

Offline Ghost Of Highbury

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Re: Additional Math Help HERE ONLY...!
« Reply #274 on: June 05, 2010, 06:21:09 am »
oh damn..........this is such a bloody hard q......i remember givin this to ma teacher and he couldnt solve it..........

there are two different cases you need to consider......the first is that he selects 3 sweets all of different kinds......u knw that he can choose any 3 flavours frm the 6 available.....the number of selections is 6C3=20

the second case is that 2 of the sweets are the same and the other one is of a different flavour. when he chooses the first sweet, he has a choice between 6 different flavours. when he chooses the second sweet he still has a choice between 6 flavours since he can select another of that

flavour. but when he selects the third sweet he has a choice of 5 flavours since two sweets have already been taken form the sixth flavour and he

cannot take a third. the number of selections is 6*5=30
so the total is 30+20=50

divine intervention!

Offline jellybeans

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Re: Additional Math Help HERE ONLY...!
« Reply #275 on: June 05, 2010, 06:33:36 am »
oh damn..........this is such a bloody hard q......i remember givin this to ma teacher and he couldnt solve it..........

there are two different cases you need to consider......the first is that he selects 3 sweets all of different kinds......u knw that he can choose any 3 flavours frm the 6 available.....the number of selections is 6C3=20

the second case is that 2 of the sweets are the same and the other one is of a different flavour. when he chooses the first sweet, he has a choice between 6 different flavours. when he chooses the second sweet he still has a choice between 6 flavours since he can select another of that

flavour. but when he selects the third sweet he has a choice of 5 flavours since two sweets have already been taken form the sixth flavour and he

cannot take a third. the number of selections is 6*5=30
so the total is 30+20=50

:o :o :o :o OMG LOL i asked my teacher as well and i think he explained it 4 times but i still had NO IDEA what he was talking about. :P i did get it for a second but then i forgot D:

ANYWAYS;

'the second case is that 2 of the sweets are the same and the other one is of a different flavour. when he chooses the first sweet, he has a choice between 6 different flavours. when he chooses the second sweet he still has a choice between 6 flavours since he can select another of that
flavour. but when he selects the third sweet he has a choice of 5 flavours since two sweets have already been taken form the sixth flavour and he
cannot take a third. the number of selections is 6*5=30'

ummm i get the first part but for the second case, why is it not 6*6*5 if he has a chance of choosing 6 diff flavours the first time, 6 the next, & 5 on his third choice?  :-[

thankyouuuus.
You said I must eat so many lemons cause I am so bitter.

Offline Ghost Of Highbury

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Re: Additional Math Help HERE ONLY...!
« Reply #276 on: June 05, 2010, 06:41:50 am »
Told ya, its a crappy q..!! i might have to look at the ms...can u post the ms link plz? ?
divine intervention!

Offline jellybeans

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Re: Additional Math Help HERE ONLY...!
« Reply #277 on: June 05, 2010, 06:42:51 am »
Told ya, its a crappy q..!! i might have to look at the ms...can u post the ms link plz? ?

haha :P
You said I must eat so many lemons cause I am so bitter.

Offline Ghost Of Highbury

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Re: Additional Math Help HERE ONLY...!
« Reply #278 on: June 05, 2010, 06:46:17 am »
The "Two of one kind" means can choose from 6 flavours .... the  "+1" means , only 5 flavours as one of the flavour doesn't exist anymore..

s 6*5...
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Offline Dibss

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Re: Additional Math Help HERE ONLY...!
« Reply #279 on: June 05, 2010, 01:05:16 pm »
5 A function f is defined by for the domain x 0.
(i) Evaluate f^2(0). [3]
(ii) Obtain an expression for f^-1. [2]
(iii) State the domain and the range of f^-1. [2]

I don't understand how to get the correct answer for part (iii) so could someone please help me?

Mark scheme attached.

Offline cooldude

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Re: Additional Math Help HERE ONLY...!
« Reply #280 on: June 05, 2010, 01:26:35 pm »
5 A function f is defined by for the domain x 0.
(i) Evaluate f^2(0). [3]
(ii) Obtain an expression for f^-1. [2]
(iii) State the domain and the range of f^-1. [2]

I don't understand how to get the correct answer for part (iii) so could someone please help me?

Mark scheme attached.

first of all the range of f^-1(x)=domain of f(x) and range of f(x)=domain of f^-1(x)
this will answer the part of the q asking the range of f^-1 wich is f^-1(x)=>0
now we use the part that range of f(x)=domain of f^-1(x) , when we subsitute 0 in (e^x)+1/4 we get 1/2, we substitute 0 as this is the minimum value in the domain given, so thus we get the range as f(x)=>0.5 and this is equal to the domain of f^-1(x), i.e. x=>0.5

Offline Dibss

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Re: Additional Math Help HERE ONLY...!
« Reply #281 on: June 05, 2010, 01:31:45 pm »
first of all the range of f^-1(x)=domain of f(x) and range of f(x)=domain of f^-1(x)
this will answer the part of the q asking the range of f^-1 wich is f^-1(x)=>0
now we use the part that range of f(x)=domain of f^-1(x) , when we subsitute 0 in (e^x)+1/4 we get 1/2, we substitute 0 as this is the minimum value in the domain given, so thus we get the range as f(x)=>0.5 and this is equal to the domain of f^-1(x), i.e. x=>0.5

Oh, i get it!
Thank you =]
+ REP

Offline cooldude

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Re: Additional Math Help HERE ONLY...!
« Reply #282 on: June 05, 2010, 01:39:06 pm »
Oh, i get it!
Thank you =]
+ REP

np and Thanks for the rep  ;D

Offline jellybeans

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Re: Additional Math Help HERE ONLY...!
« Reply #283 on: June 06, 2010, 12:24:35 pm »
:o Help pleaaaase! 5ii) THANK YOU. :P :P :P :P
You said I must eat so many lemons cause I am so bitter.

Offline J.Darren

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Do not go where the path may lead. Go instead where there is no path and leave a trail.