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Maths, Addmaths and Statistics: Post your doubts here!

Steel Arm

Steel Arm

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Firstlly you shoud have drawn the graph and all.....
now if u let y=1+2x^2 -x^3
therefore y=k as well
now the line y=k is a obviously a horizontal line......
so what you do is find the range from which this line y=k will meet the curve 3 times.....
you will see from the graph of prev part that between the point y=1 and y=2 any horizontal line between these points will meet the curve thrice
SOOOO
1<k<2
k lies between 1 and 2
 
K

Khadija_1234

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Steel Arm said:
Firstlly you shoud have drawn the graph and all.....
now if u let y=1+2x^2 -x^3
therefore y=k as well
now the line y=k is a obviously a horizontal line......
so what you do is find the range from which this line y=k will meet the curve 3 times.....
you will see from the graph of prev part that between the point y=1 and y=2 any horizontal line between these points will meet the curve thrice
SOOOO
1<k<2
k lies between 1 and 2
Click to expand...

Thank you so much! :)
 
robinhoodmustafa

robinhoodmustafa

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Steel Arm said:
Firstlly you shoud have drawn the graph and all.....
now if u let y=1+2x^2 -x^3
therefore y=k as well
now the line y=k is a obviously a horizontal line......
so what you do is find the range from which this line y=k will meet the curve 3 times.....
you will see from the graph of prev part that between the point y=1 and y=2 any horizontal line between these points will meet the curve thrice
SOOOO
1<k<2
k lies between 1 and 2
Click to expand...

>_< Damn! I left that part in my exam because I couldn't recall this y=k and intersection etc

Btw Thankyou :) Now I wont repeat this mistake in CIE. IA
 
TheStallion-Reborn

TheStallion-Reborn

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Steel Arm said:
Firstlly you shoud have drawn the graph and all.....
now if u let y=1+2x^2 -x^3
therefore y=k as well
now the line y=k is a obviously a horizontal line......
so what you do is find the range from which this line y=k will meet the curve 3 times.....
you will see from the graph of prev part that between the point y=1 and y=2 any horizontal line between these points will meet the curve thrice
SOOOO
1<k<2
k lies between 1 and 2
Click to expand...
is this maths or add maths?
 
Haris Bin Zahid

Haris Bin Zahid

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Please anyone explain me (Q7-ii-b). I know the coordinates but am confused about the nature of the stationary point with a modulus function. How on earth can it be maximum?
 

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Steel Arm

Steel Arm

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Haris Bin Zahid said:
Please anyone explain me (Q7-ii-b). I know the coordinates but am confused about the nature of the stationary point with a modulus function. How one earth can it be maximum?
Click to expand...
well modulus function means reflecting the graph of f(x) in the x-axis......
now automatically the minimum point will become a maximum
(since a reflection of a minimum pt in horizontal line gives a maximum point)
 
Haris Bin Zahid

Haris Bin Zahid

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Steel Arm said:
well modulus function means reflecting the graph of f(x) in the x-axis......
now automatically the minimum point will become a maximum
(since a reflection of a minimum pt in horizontal line gives a maximum point)
Click to expand...
But there are coordinates of y which are greater than 11.....:(
 
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