Mathematics: Post your doubts here!

[applepie1996]

Can anyone please solve winter 2012 Question 7 part ii of this winter 2012 paper 33 question. The value of k=10 .Can someone please explain how do we get it?View attachment 23763

ok so
all u do is
pie/4 times 40
so
i'm gonna refer to the shaded are as a triangle which it roughly is
area of the first triangle is A
the triangle right next to it (under the x-axis)
area of those two would be 2A and area of 3 triangles would be 3A and so on............
and then the x-coordinates will be pie/4 + pie/4+...................
now that we want 40A
we do pie/4 times 40 which is equal to 10 pie so k=10
i hope you get it

 

[syed1995]

wow sooo much p3 .. sab sir say guzar raha hai

 

[A star]

wow sooo much p3 .. sab sir say guzar raha hai

same here bro but next year me sab samajh ajae ga xD

 

[Rutzaba]

Okay so now we have to find angle between a line and plane.​

To do this we need two things we need is the b1 of the line which we can obtain by subtracting one point on the line from another on the line ​

(-5,3,6) – (5,8,1) = (-10,-5,5) this is b1​

Second thing is n1 which are the coefficients of x y and z in the equation of plane ​

I.e. = (2, -1,4)​

Now know that when a line and a plane is involved then we use sin*​

If both cases if there are angles to be found in two lines or two planes we use cos*​

Here we use sin​

​

Frst take modulus of b1= root of ((-10) ^2 +(-5)^2+ 5^2)​

(100+25+25 ) ​

=root 150​

Then of n1= root of( (2^2)(-1^2)(4^2)​

=root 21​

Now put in formula ​

B1.n1 = mod of b1* mod of b2 * sin a​

(-10,-5,5) . (2, -1,4) = root 150* root 21 sin a​

-20 +5 +20 = root 150* root 21 sin a​

-5/ root 150* root 21 = sin a​

A= sin inverse of -5/ root 150* root 21 ​

A= 5.1 ignore the negative sign as you need acute angle and other wise ul get obtuse. J​

Dun frgt me in ur prayers J and if u dint get it ask me again J​

​

applepie1996​

 

[Abu mota]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s12_qp_43.pdf
Q.2 and Q.7 iii) and iv)

 

[daviruss]

plzz help in number 6 can any one solve it for me plzz http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s08_qp_3.pdf

 

[PhyZac]

CHALLENGING QUESTION !!!

i think this question is GOING to come this year and i am 100 % sure !!
so any help ???

A ball is dropped froma height of 2m above a hard floor.
After each bounce , a ball rises to 3/4 of its previous height.

(a) how far has it travelled in total when strikes the ball for the nth term?
(b) show that the ball never travels more than 14 m in total .

i tried my best but never got it !

(a) ans is 14 - 16 * 0.75 ^n metre

ahmed abdulla syed1995 A star

This of pure 1, no Mechanics nor Physics knowledge needed.

as you did,
2(1-0.75^n)/1-0.75

but we also have to multiply with 2, since when a bounces it goes up and down so it travel the distance twice not once, except for the first where it only go down, then bounces..therefore

{[2(1-0.75^n)/1-0.75] x 2} -2
[8-8(0.75^n)] x 2 -2
16 - 16(0.75^n) - 2
14 - 16(o.75^n)


(b) sum of infinity
(2/1-0.75) x 2 -2
8 x 2 -2
16 -2
14.

 

[A star]

ahmed abdulla syed1995 A star

This of pure 1, no Mechanics nor Physics knowledge needed.

as you did,
2(1-0.75^n)/1-0.75

but we also have to multiply with 2, since when a bounces it goes up and down so it travel the distance twice not once, except for the first where it only go down, then bounces..therefore

{[2(1-0.75^n)/1-0.75] x 2} -2
[8-8(0.75^n)] x 2 -2
16 - 16(0.75^n) - 2
14 - 16(o.75^n)


(b) sum of infinity
(2/1-0.75) x 2 -2
8 x 2 -2
16 -2
14.

if this kind of question apeared only math wiz or a mechanics student wil be able to solve it correctly.

 

[PhyZac]

if this kind of question apeared only math wiz or a mechanics student wil be able to solve it correctly.

Well, whenever I solve, I draw a sketch of what the question tells, this help me while solving! In Mechanics nearly every question requires drawing for me.
So, if you get stuck try sketching, myt help!

 

[A star]

wow sooo much p3 .. sab sir say guzar raha hai

a better dialogue p3 p3 every where xD. anyway in s1 heres a good one there are 9 pies to be divided between 3 people so that each person gets a odd no of pies. in how many no of ways can they be divided. i know the answerso i am posting it so u guys can solve it and others can get help.

 

[VelaneDeBeaute]

daviruss
M/J/08 Q.6.

 

[A star]

daviruss
M/J/08 Q.6.
View attachment 23852
View attachment 23853
View attachment 23854

its p1? and i wish i had aritting like u . mine is likea chinese script

 

[GorgeousEyes]

jun2010 v11 no.1 pure 1

 

[Hassi123]

http://www.novapapers.com/images/PDF/CIE/A-LEVEL/maths/2011nov/9709_w11_qp_33.pdf
P3 q6 part 2. Its an argand diagram question! Please help

 

[A star]

jun2010 v11 no.1 pure 1

link?

 

[GorgeousEyes]

link?

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

 

[A star]

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

well we had couplr of formulaes in addmath which i remember they were tan(180-x)=-tanx , tan(90-x)=1/tanx
apply first formulae for part i you will get -k
apply second formulae for part two tan(pie/2 which is 90 - x) = 1/tanx means 1/k
for third we can use tan=perp/base to see perp=k base=1 use puthagorus theorum and you will get hyp= underroot(k^2+1)
so sinx=pep/hyp you wil get the answe

 

[GorgeousEyes]

well we had couplr of formulaes in addmath which i remember they were tan(180-x)=-tanx , tan(90-x)=1/tanx
apply first formulae for part i you will get -k
apply second formulae for part two tan(pie/2 which is 90 - x) = 1/tanx means 1/k
for third we can use tan=perp/base to see perp=k base=1 use puthagorus theorum and you will get hyp= underroot(k^2+1)
so sinx=pep/hyp you wil get the answe

Thank youu

 

[A star]

welcome

 

[Hassi123]

Someone help!!!!! http://www.novapapers.com/images/PDF/CIE/A-LEVEL/maths/2011nov/9709_w11_qp_33.pdf
P3 q6 part 2. Its an argand diagram question! Please help