Mathematics: Post your doubts here!

[PANDA-]

Vectors can be challenging sometimes... But still.. vectors in P1 are lots easier than the vectors which I did in O level Add Maths (Which I still haven't understood)

To be honest... I find vectors one of the easier topics. Functions is pretty hard..

 

[Mohsin41]

I have almost done with 10 past papers and still on 60,62/75 in P1.... grade thresholds are to high. I am worried for the final

 

[iKhaled]

To be honest... I find vectors one of the easier topics. Functions is pretty hard..

functions suck

 

[Mohsin41]

specially the functions integrated with trigonometry or the functions question which is Q10 or 11......

 

[PANDA-]

specially the functions integrated with trigonometry or the functions question which is Q10 or 11......

Yes that's especially hard. Imagine if no functions question comes in our exam, awesome.

 

[Sanis]

I have a problem in the whole vector chapter for p3 .. does anybodyhave a link for notes I can use to understand a2 vectors? thanks

 

[Mohsin41]

I have a problem in the whole vector chapter for p3 .. does anybodyhave a link for notes I can use to understand a2 vectors? thanks

If you want to have best understanding than read Pure Mathematics 2&3 OF (Hodder Education)

 

[Muhammad Muneeb]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w11_qp_12.pdf
q3 (ii)
and thanks for the help previously

 

[Alice123]

its 1 / 2*(x^2-3)

its the same thing

 

[Muhammad Muneeb]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w11_qp_12.pdf
q9 (i), how do i calculate co ordiates of D :/

 

[PANDA-]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_qp_12.pdf
q3 (ii)
and thanks for the help previously

AB = OB - OA
AB = (2-5)i+(7-1)j+(p-2)k
= -3i + 6j + 2k

Now make it a unit vector, so we can later multiply the magnitude of the vector we need (28) to get the vector itself.
For that you'll need to find the modulus by finding the square root of the sum of i^2, j^2 and k^2...

That gives you
Modulus = sqrt((-3)^2 + 6^2 + 2^2)
= 7

To find the unit vector, we need to divide our vector by the modulus, or multiply it by 1/modulus as so...

Unit vector = 1/7(-3i+6j+2k)

Multiply the magnitude (28) by the unit vector, you'll get
(1/7)(28)(-3i+6j+2k)

4(-3i+6j+2k)
Ans. = -12i+24j+8k

 

[PANDA-]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_qp_12.pdf
q9 (i), how do i calculate co ordiates of D :/

Since you're only asking about D, I'm going to guess you found M... which is (5,2)

M is the midpoint between B and D

The formula for midpoint would be..
(x2-x1)/2 , (y2-y1)/2

So (x2-x1)/2, where x2 is the x value of D, and x1 is the x value of B are equal to 5, the x value of M the midpt. Solve.
So (y2-y1)/2, where y2 is the y value of D, and y1 is the y value of B are equal to 2, the y value of M the midpt. Solve.

You'll get
x2= 7
y2= -2

 

[Muhammad Muneeb]

AB = OB - OA
AB = (2-5)i+(7-1)j+(p-2)k
= -3i + 6j + 2k

Now make it a unit vector, so we can later multiply the magnitude of the vector we need (28) to get the vector itself.
For that you'll need to find the modulus by finding the square root of the sum of i^2, j^2 and k^2...

That gives you
Modulus = sqrt((-3)^2 + 6^2 + 2^2)
= 7

To find the unit vector, we need to divide our vector by the modulus, or multiply it by 1/modulus as so...

Unit vector = 1/7(-3i+6j+2k)

Multiply the magnitude (28) by the unit vector, you'll get
(1/7)(28)(-3i+6j+2k)

4(-3i+6j+2k)
Ans. = -12i+24j+8k

Thanks man

 

[PANDA-]

Thanks man

You're welcome.

Ah, 4 days left , my preparation is lacking really.

 

[iKhaled]

You're welcome.

Ah, 4 days left , my preparation is lacking really.

how r u preparing ?

 

[Muhammad Muneeb]

You're welcome.

Ah, 4 days left , my preparation is lacking really.

4 days..... damn man..... me too....i m lacking as well.... hope it goes better there

 

[PANDA-]

how r u preparing ?

Well, past papers.

 

[iKhaled]

Well, past papers.

thats good just dont stress and u will be fine

 

[Muhammad Muneeb]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w12_qp_13.pdf
q2, how do i show if its a decreasing function?

 

[PANDA-]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w12_qp_13.pdf
q2, how do i show if its a decreasing function?

Try with 2 consecutive x values within the range, if the result is decreasing, then it is a decreasing function. I don't really know if this is a valid method, but it would work.