Author Topic: IGCSE MATHS Doubts  (Read 130657 times)

Offline haris94

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Re: IGCSE MATHS Doubts
« Reply #390 on: May 11, 2010, 03:48:12 pm »
it shld be (15.9128-15.2978)/15.2978*100 cos it it says in 2006 it wz 15.9128 n in 2007 it wz 15.2978 so ms is rite!!! :)



o yea sorry mixed 'em up  :-[
Thanks
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Offline Malak

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Re: IGCSE MATHS Doubts
« Reply #391 on: May 11, 2010, 03:48:35 pm »
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Offline Dark Prince

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Re: IGCSE MATHS Doubts
« Reply #392 on: May 11, 2010, 03:53:21 pm »
can someone tell me the difference between mutally exclusive nd non-mutally exclusive in probability......with examples....i m difficulty in probability nd in the OR rule specially the erms mentioned above.....thnkx...plzzz its urgent

Offline princess12

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Re: IGCSE MATHS Doubts
« Reply #393 on: May 11, 2010, 03:56:06 pm »
what is vulgar equation  ??? ???
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Offline Ghost Of Highbury

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Re: IGCSE MATHS Doubts
« Reply #394 on: May 11, 2010, 04:01:49 pm »
can someone tell me the difference between mutally exclusive nd non-mutally exclusive in probability......with examples....i m difficulty in probability nd in the OR rule specially the erms mentioned above.....thnkx...plzzz its urgent

i can explain better if u provide me with a q..
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Offline xMilishax

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Re: IGCSE MATHS Doubts
« Reply #395 on: May 11, 2010, 04:05:59 pm »
Anyone...?

Q9 And Q15 part b and c http://www.freeexampapers.us/IGCSE/Maths/CIE/2007%20Nov/0580_w07_qp_2.pdf

9) p = 2, q = -12

15b) 1/2a + 1/3b  15c) -1/2a +1/6b

Offline Malak

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Re: IGCSE MATHS Doubts
« Reply #396 on: May 11, 2010, 04:07:13 pm »
9) p = 2, q = -12

15b) 1/2a + 1/3b  15c) -1/2a +1/6b

umm.....Well....Can u kinda explain...?thx
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Re: IGCSE MATHS Doubts
« Reply #397 on: May 11, 2010, 04:07:30 pm »
can someone tell me the difference between mutally exclusive nd non-mutally exclusive in probability......with examples....i m difficulty in probability nd in the OR rule specially the erms mentioned above.....thnkx...plzzz its urgent

Mutually exclusive> events that are mutually INDEPENDENT of the occurrence of the other.

E.g. 1)

> From a group of six coloured balls, pick up a ball, note its colour. Replace the ball. Pick up another ball, then note the colour.

Mutually non-exclusive > events that are dependent on each other.

E.g. 2)

> From a group of six coloured balls, pick up a ball, note its colour. Pick up another ball, then note the colour.

In the 2nd example, you don't replace the ball you had first picked up. So, after the first action, there remains only 5 balls to be chosen from, i. e. the 2nd probability in 2nd example will be 1/5, instead of 1/6 as in the 1st example.

AND Multiply the probabilities. And is for "both". Both events should occur.

OR Add the probabilities. Or is for "either or", that is one of the two events.

Offline Ghost Of Highbury

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Re: IGCSE MATHS Doubts
« Reply #398 on: May 11, 2010, 04:08:31 pm »
Anyone...?

Q9 And Q15 part b and c http://www.freeexampapers.us/IGCSE/Maths/CIE/2007%20Nov/0580_w07_qp_2.pdf

ans 9) (x+2)2 = x2 + 4x + 4.

x2 + 4x + 4 -12 = x2 + 4x - 8

thus, (x+2)2 - 12
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Offline Ghost Of Highbury

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Re: IGCSE MATHS Doubts
« Reply #399 on: May 11, 2010, 04:22:28 pm »
ans 15b) Ok, get this straight first. one slant line from O towards A is a/6 and one line from O to B is b/6

To reach E from O. u have to go 3 lines towards A and 2 towards B

= 3*a/6 + 2*b/6 = a/2 + b/3

15c) EB is EO + OB

EO = -(OE) = -(a/2+b/3) = -a/2 - b/3

OB = b

hence => EB = -a/2 - b/3 + b = -a/2 + b/6
« Last Edit: May 11, 2010, 04:24:27 pm by A@di »
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Offline haris94

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Re: IGCSE MATHS Doubts
« Reply #400 on: May 11, 2010, 04:25:52 pm »
ans 9) (x+2)2 = x2 + 4x + 4.

x2 + 4x + 4 -12 = x2 + 4x - 8

thus, (x+2)2 - 12

Thanks
i got it atlast
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Offline haris94

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Re: IGCSE MATHS Doubts
« Reply #401 on: May 11, 2010, 04:28:45 pm »
7 f(x) = 10x.
(a) Calculate f(0.5).

(b) Write down the value of f -1(1).

i dont get the "b" part
how do u find the inverse of 10x  ???
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Offline Ghost Of Highbury

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Re: IGCSE MATHS Doubts
« Reply #402 on: May 11, 2010, 04:44:32 pm »
7 f(x) = 10x.
(a) Calculate f(0.5).

(b) Write down the value of f -1(1).

i dont get the "b" part
how do u find the inverse of 10x  ???

y = 10x

x = 10^y

log x = y

f(-1) x = log x

f^(-1) 1 = log 1 = 0

longer method..

which paper is this from?
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Offline Ghost Of Highbury

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Re: IGCSE MATHS Doubts
« Reply #403 on: May 11, 2010, 04:47:16 pm »
if u havent learnt log. try this method

f-1(1) means, for what value of x in 10x will u get 1

answer = 0

for e.g f(x) = x+2

          f-1x = x-2

f(2) = 4

put 4 in f-1x and u shud get 2

4 -2 = 2

see?

simple.
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Offline ksitna

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Re: IGCSE MATHS Doubts
« Reply #404 on: May 11, 2010, 05:04:16 pm »
so like whenever we have f-1 the number in brackets should be the total?
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