This discussion is now closed.

Check out other Related discussions

- Im honestly scared for maths A level
- Health and social care Level 3 is stressing me out.
- IAL Chemistry - Unit 4 EXAM DISCUSSION
- Can i give IAL Edexcel Mathmematics across 3 sessions?
- Chemistry a level AQA
- IAL Edexcel- Maths- do grades usually drop in A2
- AS Mechanics
- Math Proof Questions
- AS math edexcel tips
- summaya’s gcse journey 🎀💪
- C1 January 2002?
- Biology Paper 1
- trying to get all As for AS
- Edexcel gcse maths higher probability tree question - driving test
- probability and ratio
- Business Paper 2 WJEC
- AQA GCSE Psychology Paper 1 (8182/1) - 15th May 2024 [Exam Chat]
- OCR A Level Law 2024 Predictions
- Career selection for Physics, Mathematics, IT a levels
- ADHD- GCSEs OK- Struggling in A level. please help

I'd be gratefull if anyone could show me how to do this question:

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

Bebop

I'd be gratefull if anyone could show me how to do this question:

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

a.

(b^2-4ac) must be positive to give real solution so,

therefore b^2>=36

so b>=¦6¦ (modulus 6 i think) [to give realy] so u want -6<k<6 to give no real solution :-)

b.complete square? (x-2)^2-4+9=(x-2)^2+5

c. differentitate

d(f(x))/dx=2x-4

when 2x-4=0, x=2

Bebop

I'd be gratefull if anyone could show me how to do this question:

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

f(x) = x^2 - kx + 9, where k is a constant

a) Find the set of values of k for which the equation f(x) = 0 has no real solutions.

Given that k = 4

b) Express f(x) in the form (x-p)^2 + q, where p and q are constants to be found.

c) Write down the minimum value of f(x) and the value of x for which this occurs.

I've really forgotten how to do it.

Its a quadratic equation with

a = 1

b = -k

c = 9

a quadratic equation has no real root if

b^2 < 4ac

therefore, substituting gives:

(-k)^2 < 4*1*9

K^2 < 36

K < plus OR minus 6

so inequality is :

-6 < k <6

For second part use completing the square method to get:

(x - 2)^2 + 5

For the third part differentiate the equation to get:

2x - 4

equate this to zero to get:

x = 2

which gives f(x) = 5

differentiate again to get 2, which is greater than 0, therefore their is only one minimum value for the function.

Thank you both very, very much!

Well since I'm brushing up on the p1 I might as well get another thing cleared up.

In integration I've never felt confident knowing what to do when you have to integrate a term containing a real number divided by the root of x.

Eg. 3√x + 12/√x

I know that the root of x is equvalent to x to the power a half.

Anyway I'd appreciate any ideas on this.

Well since I'm brushing up on the p1 I might as well get another thing cleared up.

In integration I've never felt confident knowing what to do when you have to integrate a term containing a real number divided by the root of x.

Eg. 3√x + 12/√x

I know that the root of x is equvalent to x to the power a half.

Anyway I'd appreciate any ideas on this.

Bebop

Thank you both very, very much!

Well since I'm brushing up on the p1 I might as well get another thing cleared up.

In integration I've never felt confident knowing what to do when you have to integrate a term containing a real number divided by the root of x.

Eg. 3√x + 12/√x

I know that the root of x is equvalent to x to the power a half.

Anyway I'd appreciate any ideas on this.

Well since I'm brushing up on the p1 I might as well get another thing cleared up.

In integration I've never felt confident knowing what to do when you have to integrate a term containing a real number divided by the root of x.

Eg. 3√x + 12/√x

I know that the root of x is equvalent to x to the power a half.

Anyway I'd appreciate any ideas on this.

like you said, √x is the x to the half, so just treat it as x^n with n=1/2, as you would any other integral of powers of x.

ie ∫√x dx = ∫x^1/2 dx = (x^3/2)/3/2 +C = 2/3 x√x + C

and ∫(dx/√x) = ∫x^-1/2 dx = (x^1/2)/1/2 +C = 2√x +C

- Im honestly scared for maths A level
- Health and social care Level 3 is stressing me out.
- IAL Chemistry - Unit 4 EXAM DISCUSSION
- Can i give IAL Edexcel Mathmematics across 3 sessions?
- Chemistry a level AQA
- IAL Edexcel- Maths- do grades usually drop in A2
- AS Mechanics
- Math Proof Questions
- AS math edexcel tips
- summaya’s gcse journey 🎀💪
- C1 January 2002?
- Biology Paper 1
- trying to get all As for AS
- Edexcel gcse maths higher probability tree question - driving test
- probability and ratio
- Business Paper 2 WJEC
- AQA GCSE Psychology Paper 1 (8182/1) - 15th May 2024 [Exam Chat]
- OCR A Level Law 2024 Predictions
- Career selection for Physics, Mathematics, IT a levels
- ADHD- GCSEs OK- Struggling in A level. please help

Latest

Trending

Last reply 3 weeks ago

STEP 2 in 2024: Sharing Your Story! [PLUS WITH SOME SOLUTIONS AND PREDICTION]Maths

20

81