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#1 2010-06-05 14:51:28

56tracy
Guest

A couple of questions from a math test I took today

1.  Is the 5th entry in the 8th row of Pascal's triangle the number 56? 

2.  The graph of a shown function crossed the x-axis at 4 and 0.  Does this mean there are 2 real zeroes?

#2 2010-06-05 15:11:42

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: A couple of questions from a math test I took today

Hi 56tracy;

1) http://ptri1.tripod.com/


2) There could be more. There could be other crossings or there could be multiple roots.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#3 2010-06-05 17:50:22

56tracy
Guest

Re: A couple of questions from a math test I took today

Thanks Bobbym!  It appears I got those 2 questions correct.

#4 2010-06-05 17:51:23

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: A couple of questions from a math test I took today

Hi 56tracy;

That's very good!


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#5 2010-06-07 03:23:13

KrazyKyngeKorny
Member
Registered: 2010-06-07
Posts: 12

Re: A couple of questions from a math test I took today

56tracy wrote:

1.  Is the 5th entry in the 8th row of Pascal's triangle the number 56? 

2.  The graph of a shown function crossed the x-axis at 4 and 0.  Does this mean there are 2 real zeroes?

1) No, 70. The fourth entry is 56.

2) Yes. They are at x=4, and x=0.

The equation is

y = (x-0)(x-4)

which is a quadratic

y=x^2-4x

Last edited by KrazyKyngeKorny (2010-06-07 03:28:07)

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#6 2010-06-07 03:29:44

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: A couple of questions from a math test I took today

Hi;

No, not necessarily.

The equation could look like this

(x-4)(x-4)(x-4) x^3 this is a sixth degree equation. This also has crossings at 4 and 0. Just being told you have crossings at 4  and 0 does not indicate the degree of the equation.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Offline

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