Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Let f(x) = a x^3 + b x^2 + c x + d

You are given that:

1. f(3) = 5

2. f(-1) = 9

3. f(x) has its minimum at x = 0

4. f'(x) has its maximum at x = 1

How can I get back a,b,c,d?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Hi;

[answer removed]

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

How do I do this?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

[due to arguments that have fanned out to other threads, this answer is removed]

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

Test what?

Thanks for the code.

What kind of a combinatoricist notes down all his opinions in a serialised fashion?!

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,872

hi Agnishom,

By 'hand' answer:

minimum at 0 => c = 0

maximum at x = 1 => 6a + 2b = 0 => b = -3a .................(1)

subtracting

substituting (1) gives

Who needs are CAS?

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,640

Which part are you having trouble with analytically?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Hi Agnishom;

I gave you the equations.

What kind of a combinatoricist notes down all his opinions in a serialised fashion?!

A smart one.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,640

I cross-posted with bob bundy, never mind.

He's right, who needs a CAS

Offline

Bob: Thank You

who needs a CAS?

That combinatoricist from Vegas does.

Bobbym: Have you serialises your opinions like him?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,872

You're welcome.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

[All comments cleared out to prevent arguments]

**In mathematics, you don't understand things. You just get used to them.**

Offline

I was joking, of course.

The next thinks I am not a bobbymist..

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Bobbym: Have you serialises your opinions like him?

Another serious misconception. I have no opinions. All my stuff was given to me by some top ranked mathematicians. Some I can understand and use, others I just get wrong. I have never really discovered anything new in my entire life.

**In mathematics, you don't understand things. You just get used to them.**

Offline

I know that you have not serialised your opinions, not even quotes. That is why I am recording your quotes for the betterment of the society in near future.

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Hmmm, you did not read the last post. Aping RF,HW or DZ is not an opinion really. Even when I thought I had something original I always found that they got there first! You are recording their words and concepts as best as I understand them.

**In mathematics, you don't understand things. You just get used to them.**

Offline

Hi;

I was joking. I hope that you understand.

Also, I have used the CAS approach to solve the problem. I am truly grateful of the efforts your put up do carry forward the message of great mathematicians.

I hope you do not get me wrong..

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

I only wish to prevent arguments. I have removed the controversial part of the thread.

**In mathematics, you don't understand things. You just get used to them.**

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,640

bobbym wrote:

[All comments cleared out to prevent arguments]

I think bobbym has become too serious.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Why do you think that? It is my job to keep the forum running smoothly, the answer to one question takes second place to that.

**In mathematics, you don't understand things. You just get used to them.**

Offline

The solution was a nice one. Everyone likes it.

Agnishom's post brought in the controversy.

The following is what started it all:

Agnishom wrote:

who needs a CAS?

That combinatoricist from Vegas does.

Bobbym: Have you serialises your opinions like him?

The next should have removed it instead

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,640

I think I asked that.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

Hmmm, sorry I already made the decision. Can not be undone, so why discuss it?

**In mathematics, you don't understand things. You just get used to them.**

Offline

But the bobbym-protection squad is planning to arrest me for answering the question...

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,788

bobbym-protection squad

Who is that?

**In mathematics, you don't understand things. You just get used to them.**

Offline