Mathematics: Post your doubts here!

[unique840]

Thank you!!
btw wat abt the 3rd part of my other q?

value of R is 5
for least value, we substitute the value [cos(theta + alpha)] with +1 and -1
so function will be 5(1) + 7 and 5(-1) + 7
so the least value is 2

 

[abcde]

The ans is 2 nt 7.
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_s04_qp_2.pdf

AoA!
In part (a), you write this function as 5 sin (θ + 53.13).
So, 3 sin θ + 4 cos θ + 7 can be rewritten as 5 sin (θ + 53.13) + 7. The least value of this sin (θ + 53.13) part of the function is -1. Consequently, the least value of the entire function is = 5(-1) + 7 = 2.

 

[aliya_zad]

AoA!
In part (a), you write this function as 5 sin (θ + 53.13).
So, 3 sin θ + 4 cos θ + 7 can be rewritten as 5 sin (θ + 53.13) + 7. The least value of this sin (θ + 53.13) part of the function is -1. Consequently, the least value of the entire function is = 5(-1) + 7 = 2.

Thank u!!

 

[abcde]

Thank u!!

You're welcome.
@unique840: meine aap ka solution nai dekha tha. Honestly.

 

[unique840]

You're welcome.
@unique840: meine aap ka solution nai dekha tha. Honestly.

 

[allysaleemally]

Asa, im stuck at question 2, maths P1 oct 2008
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_ms_1.pdf
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_qp_1.pdf
could u please explain it to me. Thank you.

 

[abcde]

Asa, im stuck at question 2, maths P1 oct 2008
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_ms_1.pdf
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_qp_1.pdf
could u please explain it to me. Thank you.

W.S!

 

[yuliana95]

Asa, im stuck at question 2, maths P1 oct 2008
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_ms_1.pdf
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_qp_1.pdf
could u please explain it to me. Thank you.

It is about proving the identity?

Here is the answer.. hope it helps

 

[ffaadyy]

Asa, im stuck at question 2, maths P1 oct 2008
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_ms_1.pdf
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w08_qp_1.pdf
could u please explain it to me. Thank you.

[(1 + sin x) / cos x] + (cos x / (1 + sin x)]
Take the LCM and write it as a single fraction.
{[(1 + sin x)^2 + cos^2 x] / cos x(1 + sin x)}
Expand (1+sin x)^2 so that it becomes 1 + 2 sin x + sin^2 x. Now in the numerator you have
1 + 2 sin x + sin^2 x +cos^2 x. Recall the identity sin^2 x +cos^2 x = 1. Therefore, replace sin^2 x +cos^2 x with 1 in the numerator so that it becomes 1 + 2 sin x + 1. The fraction that we now have is
(2 + 2 sin x) / cos x (1 + sin x). Take '2' common from the numerator so that it becomes 2 ( 1 + sin x) / cos x (1 +sin x). ( 1 + sin x) being common is cancelled out and you are left with 2 / cos x. Thus, LHS = RHS.

 

[elbeyon]

Can any help me to find out the Co-ordinate of D by vector method (Q no. 6 ii)
Question paper : http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9709%20-%20Mathematics/9709_s07_qp_1.pdf
Marking Scheme : http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9709%20-%20Mathematics/9709_s07_ms_1.pdf

 

[ffaadyy]

Can any help me to find out the Co-ordinate of D by vector method (Q no. 6 ii)
Question paper : http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9709%20-%20Mathematics/9709_s07_qp_1.pdf
Marking Scheme : http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9709%20-%20Mathematics/9709_s07_ms_1.pdf

You'll first find the co-ordinates of C which'll be (10,0). Now as BA=CD, you can find the coordinates of D by vector move. To go from B to A, you need to move 4 places to the left on the x-axis (-1, 0, 1, 2) and 6 places upwards on the y-axis (9, 10, 11, 12, 13, 14). Now you'll simply add '4' to the x-coordinate of C and '6' to the y-coordinate of C. This'll come out to be (14,6) and thus these are the co-ordinates of D.

 

[allysaleemally]

thankss alot

 

[HubbaBubba]

May/June 2006 Question One :/ I don't understand the question.
1. A curve has equation y=k/x. Given that the gradient of the curve is -3 when x=2, find the value of the constant k. :/

 

[ffaadyy]

May/June 2006 Question One :/ I don't understand the question.
1. A curve has equation y=k/x. Given that the gradient of the curve is -3 when x=2, find the value of the constant k. :/

Differentiate 'y=k/x' using the quotient rule. The derivative will come out to be 'dy/dx=(-k) / x^2'. Then substitute the value of x=2 and the gradient (dy/dx)=-3 in this equation and calculate the value of 'k'. The value of 'k' is 12. If you are finding it difficult to differentiate, then it'll be done as follows:

y = k / x
dy / dx = [(0)(x) - (k)(1)] / x^2
dy / dx = (-k) / x^2

Substitute '-3' in the place of dy / dx and '2' in the place of x:

-3 = (-k) / (2)^2
-12 = -k
12=k

 

[ismailmz]

Mechanics 1 Doubt

http://www.xtremepapers.com/CIE/ind...l/9709 - Mathematics/&file=9709_s10_qp_42.pdf

I got the concept but cannot find out the exact answer for Q4

 

[abcde]

Mechanics 1 Doubt

http://www.xtremepapers.com/CIE/index.php?dir=International A And AS Level/9709 - Mathematics/&file=9709_s10_qp_42.pdf

I got the concept but cannot find out the exact answer for Q4

AoA!
Why not?

 

[VelaneDeBeaute]

AoA!
Had some problems with integration!

1. Find the area of the region enclosed by y = ( x - 2 ) ^ 4 and y = ( x - 2 ) ^ 3
2. Draw the graph of the function f ( x ) when the graph of the inverse function f ' ( x ) is given ! http://www.mediafire.com/imageview.php?quickkey=sllcr94vcjmb0bz
3. Find the area of shaded region

 

[Scafalon40]

a related rates of change question
Two quantities p and q are related by the equation (p-1)(q+2)=k where k is a constant. When p=5 units, q is 7 units and q is changing at the rate of 0.04 units per second. Find the rate at which p is changing.
The answer at the back of the book is 0.018 units per second
The one I'm getting is -0.018 seconds
I don't get it, where is the mistake?

 

[abcde]

AoA!
Had some problems with integration!

1. Find the area of the region enclosed by y = ( x - 2 ) ^ 4 and y = ( x - 2 ) ^ 3
2. Draw the graph of the function f ( x ) when the graph of the inverse function f ' ( x ) is given ! http://www.mediafire.com/imageview.php?quickkey=sllcr94vcjmb0bz
3. Find the area of shaded region View attachment 3503

W.S! 3. Do you know of any coordinates or the equation of the vertical line to the right of the y-axis?

 

[VelaneDeBeaute]

^No! The only thing given in the question was the equation of the curve i.e. y = 1 / (2x + 2) ^2 !
If you have that book, Pure Mathematics 1, you can see the question for yourself! Exercise 16 d, Question 5, part c !