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Mathematics: Post your doubts here!

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Hi, I need help with june 2012 p1 variant 2. Question 7. Please, I'd really appreciate it!
 
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i
il tell u wat... we haD THIS the year i sat my cie :) gimme a few mins
yeah i remember this question too. everyone was talking about the first part of this question when we did it last year. it was a tricky part and most difficult question on the paper!
 
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i did this right.
but tell me isnt a+ (n-1)(d) for arithematic progression?
and ar for geometric :/ ?
 
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Q2 find f '(x) and see that you will get two terms in x with neg sign hence for all positive values of x it will be a decreasing function
7i
y=5-x
y=11-x^2
sub y you will get 5-x=11-x^2 solve it and take the positive value of x as p and its y coordinate as q
Thanks! And I asked for 7 (ii) not (i), so could you explain that too please?
 
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yeah i remember this question too. everyone was talking about the first part of this question when we did it last year. it was a tricky part and most difficult question on the paper!
do this one... i think my p1s getting rusty...
Dug
 
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i did this in a rather long way
ending up in a simultaneous eq bringing the right answers
 

Dug

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Thanks a lot.. I have one more question.
What if the functions were:
f(x) = 3 - 2sinx for 0 ≤ x < pi
f(x) = 3 - 2sinx for 0 ≤ x < 2pi
Would there be any difference in the ranges? (Notice the domain has changed)..
Yes, it will be different!
For the first, 1 ≤ f(x) ≤ 3
For second, 1≤ f(x) ≤ 5
 
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I see you haven't understood my answer through PM's.
Anyways, the range won't change.
It would change.

there is no sin 270 here.. so no sinx=-1..

so the limits would be 3-2(0) and 3-2(1)
so
3 to 1 would be the limits.. instead of the 5 to 1 in the case of 0<x<2pi.
PANDA- I didn't wanna bother you with all those questions :)

Omg.. I'm even more confused now. Which is which?
 
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guys arithematic progression dont have 'r' they have d...
solve this q sumone
 
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Yes, it will be different!
For the first, 3 ≤ f(x) < 1
For second, 1≤ f(x) ≤ 5
Alright.. thanks
So in summary, the domain of the function affects the min & max values while the period eg. sin(ax), sin(bx) etc will not affect it. Is that right?
 
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