Mathematics: Post your doubts here!

[Wolfgangs]

http://maxpapers.com/syllabus-materials/mathematics-9709-a-level/attachment/9709_s14_qp_51/

Can someone please help me with question 4? Draw a diagram if possible.

 

[fatimarehman]

Please I need help in maths p3 question. It's paper 3 question from add maths remainder and factor theorem chapter 5 miscellaneous exercise q14 part b. I cannot write the whole question so please can anyone explain it.

 

[Harsheys]

Can someone explain to m in M1 paper 4, in work energy and power, why sometimes we consider Fv (mav) when calculating power or driving force with acceleration and sometimes we don't. An example where it is not considered is MJ 2014 pp43 Q5(ii). Whereas in ON 2012 pp42, there is a question where it is considered AND so is the component of the mass parallel to the plane.
Thanks.

 

[YenYen]

I need help with this question, it's A2 syllabus. I don't understand why the answer is - 5<x<1/3 I thought the answer is x>-5. Can someone please explain step by step please? Thank you.

Spoiler: question and working

 

[eliyeap]

I need help with this question, it's A2 syllabus. I don't understand why the answer is - 5<x<1/3 I thought the answer is x>-5. Can someone please explain step by step please? Thank you.

Spoiler: question and working

Um, instead of sub x=-6 , why don't u just sub in x=0, that way you can avoid sub in x=1. Anyway when you sub x=0 its suppose to be in 3x^2+14x-5>0 not the earlier modulus. Insert it following this method and you can get the answer.

 

[Dream.Eater]

Part (iii) anyone?

 

[Tim Ianey]

Sharing my Vector notes here to help people! http://alevelfurthermaths.blogspot.com/2015/07/revision-guide-vectors-geometry_19.html

 

[Rizwan Javed]

If f(x)= (36x^2) -(2x^4)
Find the interval for which f(x) is a decreasing function.

^Can anyone please solve it, along with explanation.

 

[The Chill Master]

9709/41/M/J/11
Question 4 (i) part
Why are we taking friction positive in one case wile negative in the other one?

Question 6 (i)
Why is C zero?

 

[The Sarcastic Retard]

If f(x)= (36x^2) -(2x^4)
Find the interval for which f(x) is a decreasing function.

^Can anyone please solve it, along with explanation.

O to 18 ?

 

[shazmina]

Can some1 help me with Question 8 part ( ii ) of this paper ...
http://onlineexamhelp.com/wp-content/uploads/2013/11/9709_s13_qp_11.pdf
The K value is 3 ...

 

[The Chill Master]

Can some1 help me with Question 8 part ( ii ) of this paper ...
http://onlineexamhelp.com/wp-content/uploads/2013/11/9709_s13_qp_11.pdf
The K value is 3 ...

The answer to your first part should be 2(x-3)^2-5
Just remember whenever they ask smallest value it's -b
And b in this case is -3 that gives us 3

 

[Copy Cat]

Last Part

 

[Rizwan Javed]

O to 18 ?

Thanks for the reply, but your answer is totally wrong Anyway, I have solved that question. If you require, following is the solution for it:
f(x)=36x^2 -2x^4
f ' (x) = 72x - 8x^3
for it to be a decreasing function, f ' (x) <= 0 , therefore,
72x - 8x^3 <= 0
9x - x^3 <= 0
x(x+3)(x-3)>= 0 ---> (1)
Critical Values: 0, -3, 3
Now drawing it on a number line:

So for (1) to be +ive, the interval satisfying it is :
-3<=x<=0 OR 3<=x

That's it!

 

[Rizwan Javed]

View attachment 55520
Last Part

4! * 3! * 2! = 288
There is only 1 person tenors who can stand with Basses. So let symbol 'X' represent Tensors who don't want to stand with basses and X" who wants , and let symbol 'O' represent Basses.

XXX X" OOOO
so if they stand in this arrangement, the number of possible arrangements for tensors, is 3! (taking the X" person stays at his position shown) and the number of possible arrangements for Basses is 4!. As there are two ways in which the teams can stand as a whole i.e: tensors on right and basses on left and vice versa, so multiplying with 2!

So total arrangements become: 3!*4!*2!

 

[Copy Cat]

4! * 3! * 2! = 288
There is only 1 person tenors who can stand with Basses. So let symbol 'X' represent Tensors who don't want to stand with basses and X" who wants , and let symbol 'O' represent Basses.

XXX X" OOOO
so if they stand in this arrangement, the number of possible arrangements for tensors, is 3! (taking the X" person stays at his position shown) and the number of possible arrangements for Basses is 4!. As there are two ways in which the teams can stand as a whole i.e: tensors on right and basses on left and vice versa, so multiplying with 2!

So total arrangements become: 3!*4!*2!

Thankx

 

[Copy Cat]

 

[Copy Cat]

 

[eliyeap]

View attachment 55540

f(x)= (6+7x)/(2-x)(1+x^2)= A/(2-x) + Bx+C/(1+x^2)
Cross Multiply: 6+7x = A(1+x^2) + Bx+C(2-x)
Let x=2: 6+7(2) = A(1+4) A = 4
Coefficient of x^2: Ax^2 - Bx^2= 0x^2
A=B , B=4
Coefficient of x: Bx - Cx = 7x
4x - Cx = 7x
-Cx = 3x
C= -3

 

[ashcull14]

show that the equation (a)sin(x-60)-cos(30-x)=1 can be written as cosx=k where k is a constant
(b) hence solve the above equation from 0<x <180

B part only pleaseeeeeeeeeeee