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Author Topic: Maths  (Read 3852 times)

nid404

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Re: Maths
« Reply #15 on: October 02, 2009, 12:04:17 pm »
we got very close answers...i think it's right
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Offline Ghost Of Highbury

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Re: Maths
« Reply #16 on: October 02, 2009, 12:08:13 pm »
Okay.
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nid404

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Re: Maths
« Reply #17 on: October 02, 2009, 12:19:06 pm »
Okay :P
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Offline Ghost Of Highbury

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Re: Maths
« Reply #18 on: October 02, 2009, 07:29:47 pm »
:P
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Offline Eamyzz

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Re: Maths
« Reply #19 on: October 07, 2009, 04:58:05 pm »
any other challenging question  ::)
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Offline Eamyzz

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Re: Maths
« Reply #20 on: October 08, 2009, 12:46:27 am »
hey all does any1 no da answer of  May/june 2009 Q9 P1
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Offline Ghost Of Highbury

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Re: Maths
« Reply #21 on: October 08, 2009, 05:59:27 am »
no idea how to solve the ii part

heres the i) find dy/dx => let u=6 ; v= 3x-2

therefore => du/dx = 0 and dv/dx = 3

dy/dx = (vdu - udv)/v2 => (-18)/(3x-2)2

apply x =2 in dy/dx
u get

-18/16 = -1.125/

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Offline astarmathsandphysics

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Re: Maths
« Reply #22 on: October 08, 2009, 04:08:28 pm »
30700/79.6-350=35.68 euros
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Offline sameer210394

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Re: Maths
« Reply #23 on: October 16, 2009, 12:05:27 am »
Quote from: ~Am~ on October 01, 2009, 07:23:32 pm
refer to the diagram attached..
.
first find the area of CBD...pir2/4 = 3.14/4 = 0.785

now, the area in peach is = y; the green area = x

total area of square = 1
square comprises of 4 peach shaded region + 4 green shaded region + 1 z
= 4y + 4x + z =1 (1)
CBD = 0.785
therefore, the area of the remaining part = 1 - 0.785 = 0.215

this area comprises of 2 peach shaded region + 1 green shaded region = 2y + x = 0.215

rearrange => y=(0.215 - x)/2     
put this value of 'y' in the (1) equation
7x + 2z = 1.785 (keep this equation in mind)

----------------------------------
now consider the sector CBD
area = 0.785
it comprises of 3 green + 2 peach + 1 z

3x + 2y + z = 0.785
substitute 'y' value here

y = (0.215 - x)/2

so that gives us...
2x + z = 0.57
--
now for the final sim. equations

7x + 2z = 1.785
2x + z   = 0.57  (*2)
--------------------
  7x + 2z = 1.785   (subtract them)
  4x + 2z = 1.14
 -----------------
   3x = 0.645
   x = 0.215

------------
substitute in any equation to find the value of z

lets use 2x + z = 0.57


(2*0.215) + z = 0.57
z = 0.57 - 0.43

z = 0.14

done!




Abbey Mallu, I solved the same question with sumit in our free period, lolz...
remember we had done these types of sums.
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Offline sameer210394

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Re: Maths
« Reply #24 on: October 16, 2009, 06:19:17 am »
Quote from: ~Am~ on October 01, 2009, 07:23:32 pm
refer to the diagram attached..
.
first find the area of CBD...pir2/4 = 3.14/4 = 0.785

now, the area in peach is = y; the green area = x

total area of square = 1
square comprises of 4 peach shaded region + 4 green shaded region + 1 z
= 4y + 4x + z =1 (1)
CBD = 0.785
therefore, the area of the remaining part = 1 - 0.785 = 0.215

this area comprises of 2 peach shaded region + 1 green shaded region = 2y + x = 0.215

rearrange => y=(0.215 - x)/2     
put this value of 'y' in the (1) equation
7x + 2z = 1.785 (keep this equation in mind)

----------------------------------
now consider the sector CBD
area = 0.785
it comprises of 3 green + 2 peach + 1 z

3x + 2y + z = 0.785
substitute 'y' value here

y = (0.215 - x)/2

so that gives us...
2x + z = 0.57
--
now for the final sim. equations

7x + 2z = 1.785
2x + z   = 0.57  (*2)
--------------------
  7x + 2z = 1.785   (subtract them)
  4x + 2z = 1.14
 -----------------
   3x = 0.645
   x = 0.215

------------
substitute in any equation to find the value of z

lets use 2x + z = 0.57


(2*0.215) + z = 0.57
z = 0.57 - 0.43

z = 0.14

done!



abbey yaar, Adi tera Answer wrong hai, the answer comes close to 0.31 . and think about this, because the area of the red outlined section was 0.57, and your answer(area of z, which is the largest portion of the red outlined part) is not even 1/3 of that area(0.57). I did this with my own method and got answer as 0.31 unit squared.
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nid404

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Re: Maths
« Reply #25 on: October 16, 2009, 07:27:38 am »
adi apna ans correct hain

sameer put down ur method,,,i can ask mam if it is right or not
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Offline sameer210394

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Re: Maths
« Reply #26 on: October 16, 2009, 07:54:54 am »
Quote from: ~Am~ on October 01, 2009, 07:23:32 pm
refer to the diagram attached..
.
first find the area of CBD...pir2/4 = 3.14/4 = 0.785

now, the area in peach is = y; the green area = x

total area of square = 1
square comprises of 4 peach shaded region + 4 green shaded region + 1 z
= 4y + 4x + z =1 (1)
CBD = 0.785
therefore, the area of the remaining part = 1 - 0.785 = 0.215

this area comprises of 2 peach shaded region + 1 green shaded region = 2y + x = 0.215

rearrange => y=(0.215 - x)/2    
put this value of 'y' in the (1) equation
7x + 2z = 1.785 (keep this equation in mind)

----------------------------------
now consider the sector CBD
area = 0.785
it comprises of 3 green + 2 peach + 1 z

3x + 2y + z = 0.785
substitute 'y' value here

y = (0.215 - x)/2

so that gives us...
2x + z = 0.57
--
now for the final sim. equations

7x + 2z = 1.785
2x + z   = 0.57  (*2)
--------------------
  7x + 2z = 1.785   (subtract them)
  4x + 2z = 1.14
 -----------------
   3x = 0.645
   x = 0.215

------------
substitute in any equation to find the value of z

lets use 2x + z = 0.57


(2*0.215) + z = 0.57
z = 0.57 - 0.43

z = 0.14

done!




Adi, the right answer goes like this.

first of all you need to eliminate the Pink portion in Fig 1. which is very simple, u have already done it.

Now we are left with the middle 'eye' like structure.(brown and white portion).

next we note that the angles in Fig 2 are always the same, 30 deg each.

now we find the yellow portion in Fig 3. by finding the area of the sector with the formula 0.5(r)2theta.

and subtract the area of the triangle. then u r left with yellow portion.

now double the area of yellow portion and you cover the following yellow area's. in Fig 4.

next we need to find the green portion which is simple again. sector formula for 30 deg.

now u add the area's of the green and yellow portion.

at this point of time you might observe you are left with white potion marked 'A' in Fig 4.

you can find this by subtracting the area found in Fig 4. from the area of the eye shape.

now twice the area of 'A' you will get the area of the light blue portion in Fig 5.

finally subtract it with the area of the eye shape again.

you will get the area of brown. which when solved is 0.31 squared units.

i Hope this was clear.
« Last Edit: October 16, 2009, 07:58:40 am by sameer210394 »
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nid404

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Re: Maths
« Reply #27 on: October 16, 2009, 07:59:48 am »
okay sameer when she first gave us the question, she gave us the hint that we needed to use the semi circle thing. But I can show this to her....It's too long a thing and she said it is not a very long thing.....No.1 she approved of our  answer.....maybe in a haste she might have....cuz i asked her during the library hours. I will ask her again
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Offline sameer210394

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Re: Maths
« Reply #28 on: October 16, 2009, 08:05:09 am »
Quote from: nid404 on October 16, 2009, 07:59:48 am
okay sameer when she first gave us the question, she gave us the hint that we needed to use the semi circle thing. But I can show this to her....It's too long a thing and she said it is not a very long thing.....No.1 she approved of our  answer.....maybe in a haste she might have....cuz i asked her during the library hours. I will ask her again

only the explanation is lengthy, if you solve it in a paper, it is less than 4 steps... try 4 ur self..

and plzz ask your teacher...
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nid404

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Re: Maths
« Reply #29 on: October 16, 2009, 08:25:17 am »
I will do that
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