IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => IGCSE/ GCSE => Math => Topic started by: holtadit on January 02, 2010, 11:43:34 am
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How would you find the inverse of
f(x) = 10^x
3y+2/y-1 = z Make Y the subject of the formula
x+a = 2x-5/a Make X the subject of the formula
PLEASE SHOW ALL WORKINGS !!
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How would you find the inverse of
f(x) = 10^x
3y+2/y-1 = z Make Y the subject of the formula
x+a = 2x-5/a Make X the subject of the formula
PLEASE SHOW ALL WORKINGS !!
y=10^x so x=log10y
Can you confirm the second question
x-2x=a-5/a
-x=a-5/a
x=5/a-1
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f(x) = 10^x
Write down the value of f^?1(1)
Using your methid for the inverse of the above function... I dont get the correct answer (the right answer is 0)
Never mind the second question
Heres another one:
simplify (x^27/27)^1.5
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for f(x)=10^x
y=10^x
x=log y to the base 10
log of 1 =0
(but i doubt u are aware of logarithm)
so f'(1) implies f(x)=1
in that case 10^x=1
therefore x=0
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Can u check the ms for the simplification so i check if mine's right and then post the steps
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zero is the right answer.
Can u do this ?
simplify (x^27/27)^1.5
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I think that 1.5 should be 2/3
if it is then the answer is (x^18)/9
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could u show me the steps, please ?
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1.5 is 3/2
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yeah.. nid is right... but astar how did u get the answer... please show me your steps !!!
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Astar meant that u may have got the powers wrong...cuz if the right ans is what astar has said....the power should be 2/3 and not 3/2
In that case
check the attachment
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one secret for ari ben canaan
http://www.wolframalpha.com/
if we have to find the inverse of f(x)=10^x
search this over there "inverse of f(x)=10^x"
its a mathematical computational engine that can help u.
make good use of the secret ari ben canaan.
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Oh. I see.
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I dont understand Question 5 paper 4 2003 november
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Which in particular or all of it? I muckd my internet up proper and now am on a phone
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5 (a) iii) iv) v)
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5 (a) iii) iv) v)
let me explain u the answers in simple english
a) iii) first of all look what the q in is asking, it is saying when the card is red OR the letter is D, which means that includes all 4 cards of red colour and the white, *D*, so that makes it 5 out of 10 cards. p(red or D)=5/10=0.5
iv) now the q asks wen the card is red AND the letter is D, so first we consider the red cards, however only one of them has the letter D on it, so that makes it 1 out of 10 cards.p(red and D)=1/10=0.1
v) now look at the q again, the q asks u to find a card that is red and has N on it. the letters on the red cards are A,D,A and M, so the p(of choosing a red card with N on it)=0
the main thing to remember is to understand the q and not only use the rules of probability (OR is addition,AND is multiplication).