Mathematics: Post your doubts here!

[Nikesh]

No i dont get the ans. 12/30+ 16/30 + 3/30 = 31/30
The ans is 5/6.

Oh sorry there has been formula mistake
it should 12/30 +16/30 - 3/30 since intersection has to be deducted as in formula of set

 

[Esme]

ok thank you

 

[iKhaled]

need help in P1 maths M/J 2009..
Q4??
http://www.xtremepapers.com/papers/...AS Level/Mathematics (9709)/9709_s09_qp_1.pdf

Plss helpp meeee.. thanks

 

[Dug]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_qp_11.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_ms_11.pdf
please explain question 9 part(ii) i don't get whats done in the marking scheme

By setting both equations equal, we get kx+6=x^2+3x+2k.
By refining the resultant equation, we get x^2 +(3-k)x +2k - 6 = 0
Set b^2-4ac = 0 and simplify.
Consequently, you get a quadratic in k. Solve it and you have the values for k.

 

[djmohammad]

salam guys: hey i need help with vectorx for AS pure maths (p1) can any1 provide me a link or sumthing for vectorx???

 

[Dug]

need help in P1 maths M/J 2009..
Q4??
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s09_qp_1.pdf

Plss helpp meeee.. thanks

Where are u stuck? Are you done with the first part?

 

[hm12]

By setting both equations equal, we get kx+6=x^2+3x+2k.
By refining the resultant equation, we get x^2 +(3-k)x +2k - 6 = 0
Set b^2-4ac = 0 and simplify.
Consequently, you get a quadratic in k. Solve it and you have the values for k.

but why did you set the two equations equal shouldn't there gradients be equal?

 

[iKhaled]

Where are u stuck? Are you done with the first part?

i am stuck in the all of the question

 

[roadtrip9o9]

hey dug thanks a lot for the last post can u tell me any more basics for the past - paper questions on functions .. involving completed square forms n finding 'A' 1,1 functions , domains ranges of inverses , findhing range when x has a domain of real values n all etc etc... Would appreciate it a LOT

 

[hm12]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_qp_12.pdf
http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_ms_12.pdf
please explain question 3 part (iii)

 

[roadtrip9o9]

also the minimum value maximum value in functions and their methods etc thanks

 

[Jimmy Russels]

Assalamalaikum. These are probably stupid questions so don't laugh Can anyone help me?
Qs.1) Find the values of k such that the straight line y=2x+k meets the curve with equation x^2+2xy+y^2=5 exactly once.

Qs.2) An Open cylindrical wastepaper bin, of radius r cm and capacity Vcm^3 is to have a surface area of 5000 cm^3.
(a) Show that V=1/2r(5000πr^2)
(b) Calculate the maximum possible capacity of the bin.

 

[Dug]

need help in P1 maths M/J 2009..
Q4??
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s09_qp_1.pdf

Plss helpp meeee.. thanks

i)
'a' is the amplitude of the function.
a = 9 - 3 = 6

'b' is the number of cycles if in 2pi
The graph shows 2 cycles in 2pi and therefore b = 2

'c' is the y-intercept. Its the number of units the graph has shifted upwards.
c=3

ii) You got the values of a, b and c.
y = 6sin2x + 3
For y = 0,
6sin2x + 3 = 0
sin2x = -1/2
2x = 7pi/6
x = 7pi/12

We could've got another solution too but the question asks for the 'smallest' value of x and thats why we exclude the value from the 4th quadrant.

 

[iKhaled]

i)
'a' is the amplitude of the function.
a = 9 - 3 = 6

'b' is the number of cycles if in 2pi
The graph shows 2 cycles in 2pi and therefore b = 2

'c' is the y-intercept. Its the number of units the graph has shifted upwards.
c=3

ii) You got the values of a, b and c.
y = 6sin2x + 3
For y = 0,
6sin2x + 3 = 0
sin2x = -1/2
2x = 7pi/6
x = 7pi/12

We could've got another solution too but the question asks for the 'smallest' value of x and thats why we exclude the value from the 4th quadrant.

thank you so much..but dude what do u mean by "a - 9 therefore 3=6"..didnt get that

 

[Dug]

hey dug thanks a lot for the last post can u tell me any more basics for the past - paper questions on functions .. involving completed square forms n finding 'A' 1,1 functions , domains ranges of inverses , findhing range when x has a domain of real values n all etc etc... Would appreciate it a LOT

Its a bit difficult to explain it like that. If you could get a question from past-papers involving those concepts, I will be grateful.

 

[roadtrip9o9]

Yea but i want to start with the basics so :/

 

[Dug]

thank you so much..but dude what do u mean by "a - 9 therefore 3=6"..didnt get that

a = 9 - 3
a = 6
Sorry I mixed up the lines.

 

[Dug]

Yea but i want to start with the basics so :/

'Start' ?
You don't have exams in this session?

 

[iKhaled]

a = 9 - 3
a = 6
Sorry I mixed up the lines.

its ok..sorry if i am annoying u but is it 9-3 cuz it didnt start from 0?

 

[Dug]

its ok..sorry if i am annoying u but is it 9-3 cuz it didnt start from 0?

Exactly!! If it started from the origin, then 'a' would have been equal to 9. You could tell that just by looking at the graph.