Mathematics: Post your doubts here!

[Mayedah]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w05_qp_1.pdf
Question 5 part (i)
why do we use 12-h rather thn simply using h of the cylinder in the similar triangle formulae ?

 

[Fatima18]

f(x)=g(x)
So
k-x=9/(x+2)
(k-x)(x+2)=9
kx+2k-x^2-2x=9
-x^2+(k-2)x+2k-9=0
or
x^2+(2-k)x+9-2k=0

For Two Equal and real roots > b^2-4ac=0

(k-2)^2-4(-1)(2k-9)=0
k^2-4k+4+8k-36=0
k^2+4k-32=0

k = 4 or -8

now solve substituting values of k

for k=4
x^2+(2-k)x+9-2k=0
x^2+(2-4)x+9-2(4)=0
x^2-2x+1=0

root = 1

for k=-8
x^2+(2-k)x+9-2k=0
x^2+(2-(-8))x+9-2(-8)=0
x^2+10x+25=0

root = -5

so the values of k are 4 or -8. and the roots for these values are 1 and -5.

PS. Well i might have made some sign mix-ups while copying the solution from my copy ..

That was rele well explained! Thanx

 

[Fatima18]

Heyzzz
http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s06_qp_1.pdf
Can someone please solve number 5??
http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w06_qp_1.pdf
Number 10 v????
Thank you!

 

[Rahma Abdelrahman]

Heyzzz
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s06_qp_1.pdf
Can someone please solve number 5??
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w06_qp_1.pdf
Number 10 v????
Thank you!

Q5. The 2 points r (3,6) and (0.75,3) and the distance is 3.75 units.. right?
u have 2 eqns (y2=12x) and (3y=4x+6)
Write 2nd eqn as (x=(3y-6)/4) and substitute in 1st equation, u will get 6 and 3 as values of y... then substitute in any of the equations to get x.. now we have 2 pts.. find the distance b/w them..

Q10 v ,, here u have to equate the g(x) to 10.
U shd take (square root of x as any other variable,, let it be z
then solve the equation as a quadratic--> z2-3z-10
u will get 5 and -2.. so equate each of them to (square root of x) so answers will be 5 squared and (-2)squared to get 25 and 4.

 

[Rahma Abdelrahman]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w05_qp_1.pdf
Question 5 part (i)
why do we use 12-h rather thn simply using h of the cylinder in the similar triangle formulae ?

It depends upon which 2 shapes u r using..
there r many different combinations that can be used..
Which 2 trinagles did u use?

 

[nooshi]

i need help in M/J 2011 Mechanics1 question 4 and 5?
:3

 

[GorgeousEyes]

Pleasee Mechanics1 June2005 no.4 .

 

[GorgeousEyes]

i need help in M/J 2011 Mechanics1 question 4 and 5?
:3

which variant ?

 

[Rahma Abdelrahman]

Mechanics... not my thing , sorry

 

[GorgeousEyes]

can any one help me with June 2005 Q7 iii
June 2009 Q10 ii - iii
pure 1 .

 

[Rahma Abdelrahman]

can any one help me with June 2005 Q7 iii
June 2009 Q10 ii - iii
pure 1 .

Q7.. when u sketch the curve, from 0 to 90 it curves down then bends upwards.. this bending shd mean that the curve doesnt have an inverse but if u stop at 90 degrees, it can have an inverse... so answer is 90.(am sure u didnt get what i meant but try,i think it is considered a fact)
Q10.. ii) minimum point has x=3 as the line of symmetry.. and since lower limit is zero, u multiply 3 by 2 (they said has a line of symmetry) if they would have said "has an inverse" the answer would have been 3.
iii) The minimum point has y coordinate as -5, so f(x) >-5 , then when u substitute x=0, u get y = 13 as upper limit.
(Math is difficult to explain when i dont have the person in front of me LOL )

 

[GorgeousEyes]

Q7.. when u sketch the curve, from 0 to 90 it curves down then bends upwards.. this bending shd mean that the curve doesnt have an inverse but if u stop at 90 degrees, it can have an inverse... so answer is 90.(am sure u didnt get what i meant but try,i think it is considered a fact)
Q10.. ii) minimum point has x=3 as the line of symmetry.. and since lower limit is zero, u multiply 3 by 2 (they said has a line of symmetry) if they would have said "has an inverse" the answer would have been 3.
iii) The minimum point has y coordinate as -5, so f(x) >-5 , then when u substitute x=0, u get y = 13 as upper limit.
(Math is difficult to explain when i dont have the person in front of me LOL )

Ya rahmaaa thank youu .. hahaha bas msa shr7ty 7elw

 

[nooshi]

variant 42

 

[Raiyan3]

Pleasee Mechanics1 June2005 no.4 .

4.i) In this one we use the formula F=ma instead of F, i will use T, since T(tension) is the force working here.
So for Particle A , (there is no friction, only weight and tension) 2-T=0.2a
For particle B , (there is friction and tension) T - uR= 0.3a << in this equation i used Friction=uR(u is the coefficient of friction)
Now we have 2 equations 2-T=0.2a
T-uR=0.3a
Cancel out the Ts. And since its not moving(limiting equilibrium) acceleration = O
We end up with 2-u3=o , u= 2/3 (3 is the normal contact force=R)

4.ii)Since there is upward force acting upon it, we need to find the new normal contact force. So, R = downward force - upward = 3 - 1.8 =1.2
Now also find out the friction =uR = 2/3 x 1.2 = 0.8
We make the equation for new force X.(its going to right away from pulley) X = Frictional Force + Tension
We don't have the tension we find it out by the help of particle A.(tension is same on the both sides)
For particle A, only weight is working. so Weight - Tension = 0 (cause there is no acceleration)
2 - T = 0 , T= 2
Now we can find out X, X= Frictional Force + Tension
= 0.8 + 2 = 2.8
Hope it helped

 

[Farru]

Question no 5, part 1. I think it simple, but don't know y im not getting the ryt ans. :/

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s10_qp_63.pdf
JazakAllah!

 

[PhyZac]

Question no 5, part 1. I think it simple, but don't know y im not getting the ryt ans. :/

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_63.pdf
JazakAllah!

As the questions says, the random variable X is the sum of the two digits

So the probability of having 2 can occur under two conditions, if the first number is 0 and second 2 or when first is 2 and second is 0

Now try solving it can u do it?

 

[Farru]

u do it please.. :$

 

[PhyZac]

u do it Please..

Okay,

When first is 0 and second is 2,
6/10 x 3/7
=9/35

When first is 2 and second is 0
3/10 x 4/7
=6/35

Now add both
9/35 + 6/35 = 3/7

If you have any question feel free to ask.

 

[Farru]

Ahh. I gt it.. Thankss.

 

[tompapaya]

questions abt statistics
thanks a lot！！