Math Is Fun Forum

ccmint

Member

Registered: 2009-10-11

Posts: 22

Why do we find the zeros of a function?

I know it's to see where the function crosses the x-axis, but what does this actually mean and how is this useful? How is this useful in a real world example?

Thanks!
John

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Why do we find the zeros of a function?

Hi John;

I'll try and explain with no jargon and no tough concepts.

I know it's to see where the function crosses the x-axis,

That is exactly what it means graphically. It is the point on the graph where y = 0.

but what does this actually mean and how is this useful? How is this useful in a real world example?

Algebraically, a root or a zero is the solution to an equation. You solve for them using the rules of algebra.

Here is a really simple example.

Three guys want to split 18 dollars. How much does each dude get?

We form the equation 3 x = 18 which is really 3x - 18 = 0 or 3x - 18 = y when y = 0

http://www.mathsisfun.com/graph/functio … =-8&ymax=8

Look where it crosses the x axis, that is a zero or a root of the equation 3x - 18 =0. It is also the answer to the real world problem of how much each guy gets. You can see that it crosses at x = 6

You also could have solved it algebraically:

3x = 18 divide both sides by 3

x = 6 So each guy gets 6 bucks.

Last edited by bobbym (2009-11-03 05:06:15)

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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.

ccmint

Member

Registered: 2009-10-11

Posts: 22

Re: Why do we find the zeros of a function?

If I understand this correctly, we graph an equation, where it intersects the x-axis is the answer to that equation. And the answer is called the root or the zero of the equation.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Why do we find the zeros of a function?

Hi John;

Yep. Good work. Of course, each problem has a different equation.

And there is more. Dive in as deep as you want.

http://www.mathsisfun.com/definitions/root.html

Last edited by bobbym (2009-11-03 05:56:16)

---

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.

ccmint

Member

Registered: 2009-10-11

Posts: 22

Re: Why do we find the zeros of a function?

Thanks, Bobby.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Why do we find the zeros of a function?

Your welcome! Post again if you get into trouble.

On another forum where I moderate, all I do is peoples homework. Pleasure to have someone asking a real question.

Last edited by bobbym (2009-11-03 06:08:16)

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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.

Sarah12

Guest

Re: Why do we find the zeros of a function?

Good John.You are going to be So happy.