Maths (Paper 3)

[fluffycloud]

I still dont get how to find max and min arg z and greast and lest modules of z
Could somebody help me out?

 

[MukeshG93]

I still dont get how to find max and min arg z and greast and lest modules of z
Could somebody help me out?

Read back in the thread, I have even posted a diagram that I made myself strictly for the purpose of posting on this thread.

 

[ahmed t]

oh sorry fatema was lookin at 31
all u done wrong is the x^2 term
it is (-3)(-4)/2! (2x)^2
that will be 12/2 4x^2
so it will be 24X^2

 

[lowjhg]

Show that the equation of the tangent to the curve at the point with parameter t is
x sin t + y cos t = a sin t cos t. [3]
(iii) Hence show that, if this tangent meets the x-axis at X and the y-axis at Y, then the length of XY
is always equal to a.


URGENT THANKS :d

Since the tangent meets at the x axis at x, y=0
Thus, x=a cos t, (a cos t, 0)
Since tangent meets at the y axis at Y, x=0
Thus, y=a sin t, (0, a sin t)

To find distance between 2 points on a graph = {[(Y2-Y1)^2]+[(X2-X1)^2]}^0.5

Distance of XY = {[(a sin t)^2]+[(-a cos t)^2]}^0.5
= [(a^2 sin^2 t)+(a^2 cos^2 t)]^0.5
= [a^2 (sin^2 t + cos^2 t)]^0.5, since sin^2 t + cos^2 t =1,
= [a^2 (1)]^0.5
= -a(n.a.), +a

Thus, the length is shown always to be a when the tangent passes through X and Y.

 

[shiningstar]

at fatema
did u square the 2 on the RHS?

square wat 2 on the right hand side? y do u have 2 square, can u please write down the working for me, sorry for the trouble. and also the same paper nov 2010 paper 33 qn no 5... i dont get ln50 :S

For Q5: Solve (2x+7)/((2x+1)(x+2)) as partial fraction which will be 4/(2x+1) - 1/(x+2)
so by Integrating this fractions with the limits 0 to 7
Which will give: (2 ln (15) - ln(9)) - (2ln(1) - ln(2))
= (ln (15^2/9) + ln(2))
= ln(25*2) = ln50

Hope I helped

 

[ammarelahi]

J10 P31 Q9 help !!

 

[shiningstar]

J10 P31 Q9 help !!

which part do you want i) or ii) ??

 

[ahmed t]

already been mentioned in this topic
all u do is find dy/dx
then find the negative reciprical

 

[ChariDon]

Guys is there any way to post images in XPF. I could give some ideas about argand diagram. Pictures speak more.

 

[MukeshG93]

Yes there is charidon. And here comes one right now. This is for those who don't get the shading idea.

 

[samy]

mayjune 10 paper 31 quest 4 part i)...
cant expand it..plzz help!!

 

[ChariDon]

 

[diwash]

@MukeshG93..Check ur PM.. I have posted my small query...

 

[ahmed t]

post it here aswell pls

 

[diwash]

@MukeshG93..

Am I right?
1. Max and min modulus...
Is it ...draw a tangest to the LOWEST PART OF THE CIRCLE (from the origin)...and then add the modulus of the center of the circle and the radius if maximum modulus needed .....and subtract radius of circle from modulus of the center of the circle if minimum modulus needed...

2. max and min argument
is it ...draw a tangent to the LOWEST PART OF THE CIRCLE (from the origin) for the least argument and HIGHEST PART OF THE CIRCLE (from the origin) for the maximum argument..and use the pythagorous theoram to get the respective value of mod Z

 

[ahmed t]

i think for modulus u draw a line from the origin through the center of the circle and the minimum mod is when it first touches the circle (intersects) and max mod is wen it intersect the circle while leaving it
correct me if im wrong

 

[WellWIshER]

it takes ages to do past papers..

i just reached 2007

 

[Madiha :)]

i think for modulus u draw a line from the origin through the center of the circle and the minimum mod is when it first touches the circle (intersects) and max mod is wen it intersect the circle while leaving it
correct me if im wrong

yess u r rite=)

 

[MukeshG93]

This should help explain the shading business

Picture courtesy of Charidon:

 

[ChariDon]