Mathematics: Post your doubts here!

[Magenta]

Hi, I need help with june 2012 p1 variant 2. Question 7. Please, I'd really appreciate it!

 

[Rutzaba]

Hi, I need help with june 2012 p1 variant 2. Question 7. Please, I'd really appreciate it!

link

 

[Magenta]

link

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s12_qp_12.pdf
Question 7. Thanks!

 

[danyaljamil]

some one please help with q7 part 2 thanks
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w12_qp_13.pdf

 

[Rutzaba]

i

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_qp_12.pdf
Question 7. Thanks!

il tell u wat... we haD THIS the year i sat my cie gimme a few mins

 

[iKhaled]

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!

 

[Rutzaba]

i did this right.
but tell me isnt a+ (n-1)(d) for arithematic progression?
and ar for geometric :/ ?

 

[WayneRooney10]

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?

 

[Magenta]

i did this right.
but tell me isnt a+ (n-1)(d) for arithematic progression?
and ar for geometric :/ ?

Yes, yes. Different formulas for sum though.

 

[Rutzaba]

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

 

[Rutzaba]

Yes, yes. Different formulas for sum though.

but the ms is showing opposite :O

 

[Rutzaba]

i did this in a rather long way
ending up in a simultaneous eq bringing the right answers

 

[Dug]

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

 

[syed1995]

i did this in a rather long way
ending up in a simultaneous eq bringing the right answers

That's how I solved it as well.. i think that's the correct way.

 

[salvatore]

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?

 

[Rutzaba]

guys arithematic progression dont have 'r' they have d...
solve this q sumone

 

[MustafaMotani]

guys arithematic progression dont have 'r' they have d...
solve this q sumone

which.?

 

[Rutzaba]

which.?

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s12_qp_12.pdf
7...
the ms shows opposite

 

[Rutzaba]

PANDA- I didn't wanna bother you with all those questions

Omg.. I'm even more confused now. Which is which?

relax... take a break and cum bak later. study sumthing other than math fr a whiile

 

[salvatore]

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?