Mathematics: Post your doubts here!

[shanky631]

Hey everyone,
Does any one have a copy of the formula sheet which is given in maths??
thanks

You will find it in the syllabus.
http://www.xtremepapers.com/papers/...d AS Level/Mathematics (9709)/9709_y12_sy.pdf

 

[shanky631]

Doubt in a2 vectors. Plz can solve someone this question.

 

[elbeyon]

Can anyone explain how to obtain the values of "a" and "b" ( I got that of c, it was quite easy). How does difference in amplitude ( 9 -3 =6 ) gives the value of "a" and 2 complete oscillations gives value of "b" as 2 ? I mean how is "a" related to amplitude and "b" to oscillations ?

Question no. 4 i. May/June 2009 Paper 1.
http://www.xtremepapers.com/papers/...AS Level/Mathematics (9709)/9709_s09_qp_1.pdf

 

[Farru]

How can we find out the value of domain for which the inverse of the function is maximum? :/

 

[Farru]

just find the dy/dx of the eq. it will be as follows:
9x^2 -12x + 4 = dy/dx
now use completing square .

it will be like

3(3x -2 )^2 -4 + 4 = y this resembles the eq. of curve i.e y = mx + C


here m = (3x - 2)^2 having squre on it proves that it can never be negative I am not sure that I have explained good enough but it is somehow this way.

Thanks Alot!

 

[Kirabo Takirambudde]

Please help with this question!!
3. Calculate the number of four digit even number can be formed from the digits 3, 4, 5,6 and 9 without repetitions
Apparently the answer is 72???

 

[whitecorp]

whitecorp plz help me in this question.

View attachment 16218

Here are the solutions. Hope it helps. Peace.

 

[whitecorp]

Please help with this question!!
3. Calculate the number of four digit even number can be formed from the digits 3, 4, 5,6 and 9 without repetitions
Apparently the answer is 72???

The last digit of this even number can be either 4 or 6, ie there are two choices for the last digit.

Once the last digit is selected, you have 3 remaining front digits, and 4 unique numbers to choose from.

For this, there are 4C3*3!=4*6=24 ways

Hence, total number of ways =24*2 =48 ways (shown)

Pretty positive 72 is incorrect.

Hope this helps. Peace.

 

[whitecorp]

Frequency is determined by B for eg in Cos2X the time period will be doubled in 360....

If frequency is doubled, period is halved. One cycle is completed in 180, not 360. Peace.

 

[iKhaled]

hey i need help in sketching the inverse of f(x) for this question.. october november 2010 question 7(ii)

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w10_qp_13.pdf

 

[whitecorp]

Doubt in a2 vectors. Plz can solve someone this question.
View attachment 16286

Solutions for your vectors problem. Hope it helps. Peace.

 

[whitecorp]

hey i need help in sketching the inverse of f(x) for this question.. october november 2010 question 7(ii)

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w10_qp_13.pdf

Reflect the original function in the line y=x, such that the domain of f^-1 (x) = range of f(x), and range of f^-1(x) =domain of f(x).

Hope this helps. Peace.

 

[Farru]

please tell me how to solve this.
ques 1, all the parts :/ Asap, thanks.

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_s10_qp_11.pdf

 

[whitecorp]

please tell me how to solve this.
ques 1, all the parts :/ Asap, thanks.

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_11.pdf

tan (pi -x) = -tanx =-k

tan(pi/2 -x ) = cot x =1/tanx =1/k

To find sinx, try drawing out a right angled triangle. Label the opposite side as k and the adjacent side as 1 such that tanx =k

Then sin x =opposite side/ hypotenus side = k/ sqrt (k^2 +1) (shown)

Hope this helps. Peace.

 

[shanky631]

Solutions for your vectors problem. Hope it helps. Peace.

Thanks a lot whitecorp. it really helped. You are awesome!!

 

[Farru]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_s10_qp_11.pdf

ques no, 5, ii.
help asap!

 

[InnocentAngel]

Please Help me with this buddies :
What is meant by real values of x ??? Does it include negative values ??
And How do we round 369,335.3 to 3 sf ? Is it 370,000 or 369,000 ?

 

[InnocentAngel]

http://www.xtremepapers.com/papers/...AS Level/Mathematics (9709)/9709_s04_qp_1.pdf
N.10 part (iv)
Why dont they accept two parallel lines?
I just dont get it !
if we have to draw the inverse, we have to reflect it in y=x .As such ,they will always be parallel lines . plz help asap

 

[bamteck]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s04_qp_1.pdf
N.10 part (iv)
Why dont they accept two parallel lines?
I just dont get it !
if we have to draw the inverse, we have to reflect it in y=x .As such ,they will always be parallel lines . plz help asap

Solve for f(x) = f-'(x)
then you will get the point of intersection !

 

[Amy Bloom]

http://www.xtremepapers.com/papers/...AS Level/Mathematics (9709)/9709_s09_qp_1.pdf
Questions 4 and 9