Maths, Addmaths and Statistics: Post your doubts here!

[syed1995]

LoL dude....this is Add. Maths, not simple maths!

Gah! thank god .. I don't have addmaths past papers .. and you should have specified dude ..

 

[Haris Bin Zahid]

Gah! thank god .. I don't have addmaths past papers .. and you should have specified dude ..

Ok sorry.....by the way I solved it. You're right it cannot be done without the aid of a diagram!

 

[Haris Bin Zahid]

Need Help in Question 9 a(ii) http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_s11_qp_21.pdf

The Histogram is needed for solving the question. Too easy.

 

[syed1995]

Ok sorry.....by the way I solved it. You're right it cannot be done without the aid of a diagram!

most of the questions where it mentions the diagram in them .. like "as shown in the diagram" the diagram is usually important to the question

 

[sifat azeem]

how many papers should we do to get an A*?

 

[Spidey21]

how many papers should we do to get an A*?

ALL

 

[Haris Bin Zahid]

Q. The function f : x---> 2x^2-6x+5, for the domain 1<=x<=4. Find the range of f.

 

[asd]

Q. The function f : x---> 2x^2-6x+5, for the domain 1<=x<=4. Find the range of f.

1 se 13?

 

[Haris Bin Zahid]

1 se 13?

No, it's 0.5 se 13.
I also did the way u did.

 

[asd]

No, it's 0.5 se 13.
I also did the way u did.

year ?

No, it's 0.5 se 13.
I also did the way u did.

it will be o.5 se 13. because using the 'completing the sqaure' method you'd get the value of k to be 0.5
a(x-h)^2 +k

 

[Haris Bin Zahid]

year ?

it will be o.5 se 13. because using the 'completing the sqaure' method you'd get the value of k to be 0.5
a(x-h)^2 +k

June 96.
Oh man.....from where did this completing square come from?
I don't think that it's relevant here.

 

[asd]

June 96.
Oh man.....from where did this completing square come from?
I don't think that it's relevant here.

It's completely relevant lmao, this can tell you the full nature of the curve.

 

[Haris Bin Zahid]

It's completely relevant lmao, this can tell you the full nature of the curve.

Ok then....thnx for helping.

 

[Haris Bin Zahid]

It's completely relevant lmao, this can tell you the full nature of the curve.

Is the domain a possible set of x-values and range of y-values?

 

[asd]

Is the domain a possible set of x-values and range of y-values?

Exactly, the range tells you the +ve positive and -ve height of the graph, like how high and low does it go in y-values. While the range, is to what extent the graph goes to the left/right. So for a restricted domain, like the one above, you will have restricted range, and vice versa. If not restricted, the curve will go all the way up (vertically--on y-axis) to infinity, and the range will only be, greater and equal to 0.5.

 

[Haris Bin Zahid]

Exactly, the range tells you the +ve positive and -ve height of the graph, like how high and low does it go in y-values. While the range, is to what extent the graph goes to the left/right. So for a restricted domain, like the one above, you will have restricted range, and vice versa. If not restricted, the curve will go all the way up (vertically--on y-axis) to infinity, and the range will only be, greater and equal to 0.5.

Can u explain how is this completing square related to range and domain???????

 

[asd]

Can u explain how is this completing square related to range and domain???????

are you an add math student?>

 

[Haris Bin Zahid]

are you an add math student?>

Yup......I've just started on my own from Quadratic functions. Doing past papers of this topic.
Em also in search of a teacher.....I hope it can be covered in 7-8 months.

 

[asd]

Yup......I've just started on my own from Quadratic functions. Doing past papers of this topic.
Em also in search of a teacher.....I hope it can be covered in 7-8 months.

The general equation is : a(x-h)^2 + k.
Now if you expand this you will get: ax^2 - 2ahx + ah^2 + k
Compare this with the equation given. a is the coefficient of x^2, so look for the co efficient of x^2 in the equation given, It is 2. so a =2 .
Likewise, -2ah = -6 (coefficients of x). this will get you h = 3/2.
(ah^2 + k) is constant, it has no x. so equate it to 5. You get, k= 1/2
In the general equation, (x-h)^2 = 0 is the x coordinate of the point when the curve has a turning point (either a maximum/minimum).
Put in the value of h, and you'll get: x=3/2 . And k is the y-value of the turning point. 3/2 = 1.5, which lie within the domain, so k i.e 0.5 is the minimum value, and calculate the maximum value of the range, i.e when x = 4.

 

[Haris Bin Zahid]

Exactly, the range tells you the +ve positive and -ve height of the graph, like how high and low does it go in y-values. While the range, is to what extent the graph goes to the left/right. So for a restricted domain, like the one above, you will have restricted range, and vice versa. If not restricted, the curve will go all the way up (vertically--on y-axis) to infinity, and the range will only be, greater and equal to 0.5.

In this question, after completing square, we get 2(x-1.5)^2+0.5.
Thus, h=1.5 and k=1/2.
This means that for this domain, the least value for y is 1/2 and it occurs when value of x is 1.5
As the graph has a minimum point, the domain would be restricted bcz otherwise the graph would never end
Now we have to look at the limit of domain, which is 4.
By substituting x=4 in the equation, we get 13
So the answers are 1/2 and 13. Is that right?

 

[asd]

Yup......I've just started on my own from Quadratic functions. Doing past papers of this topic.
Em also in search of a teacher.....I hope it can be covered in 7-8 months.

Oh and the final equation you'll get will be : 2(x-3/2)^2 + 1/2