How do I find the domain of this function?

- anonymous

How do I find the domain of this function?

- katieb

I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!

At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your **free** account and access **expert** answers to this

and **thousands** of other questions

- anonymous

\[g(x) \sqrt{x^2 - 3x - 40}\]

- anonymous

I have \[\sqrt{(x-8)(x+5)} \]

- anonymous

\[(x-8)(x+5) \ge 0\]

Looking for something else?

Not the answer you are looking for? Search for more explanations.

## More answers

- anonymous

The original problem is at the top.

- anonymous

Draw a number line and see for it

- anonymous

I don't know what x can't be though

- anonymous

I know the answer but I don't know how to get the answer.

- anonymous

(-infinity , 5] U [8 , infinity)

- anonymous

yeah but how do I find that?

- anonymous

just do trial and error method...)

- anonymous

(x−8)(x+5)≥0

- anonymous

luk for the vlue of x which satisfies this...

- anonymous

There must be a logical way to find the answer, right?

- ganeshie8

(x-8)(x+5) >= 0
its a parabola, right ?

- anonymous

I could input it into my graphing calculator but other wise I don't know how to tell if its a parabola or not.

- ganeshie8

y = ax^2 + bx + c is a parabola

- ganeshie8

any quadratic function gives a parabola graph

- anonymous

ok

- ganeshie8

can you find the x intercepts ?

- ganeshie8

once you find x-intercepts, you would know where the parabola dips into x axis (goes negative)

- ganeshie8

|dw:1346519548989:dw|

- anonymous

Oh ya that would be the point at which the g(x) function is 0, so its x - 8 = 0, x = 8, x+ 5 = 0, x=-5, and since its a parabola the graph only passes through zero twice. Nice dude, so the domain is (-infinity, -5] U [8, +infinity]

- ganeshie8

yeah nice you got it :)

- anonymous

@ganeshie8

- anonymous

Awesome, thanks again. Is there a way I could recognize any graph's shape or at least some and would you recommend memorizing those?

- ganeshie8

if the degree is 2, then its a parabola

- ganeshie8

finding domains for other polynomials is bit tricky... as they may dip into x-axis multiple times

- anonymous

okay

- ganeshie8

do you knw sketching polynomilas (end behiavior thingy )

- anonymous

never heard of it

- ganeshie8

end behavior helps you sketch ANY polynomial freehand

- anonymous

Thanks dude, I'll look it up

- ganeshie8

process is basically :
1) find x intercepts
2) using end-behavior sketch the graph by hand

- ganeshie8

its easy concept and worth learning... im sure you wil get hang of it in few minutes....... good luck :)

- anonymous

why is it that a polynomial with a degree of two is a parabola?

- anonymous

Thanks again.

- ganeshie8

uhh il have to think...... idk exactly... i think it has something to do with local maximum/minimum + increasing/decreasing thingy. we need to turn to calculus for proper understanding. im also learning... . so im no good for answering this :(

- ganeshie8

@mukushla @eliassaab @experimentX

- anonymous

Oh, I have enough to learn for now so it doesn't matter to me. I bet I wouldn't understand the explanation if it involves terms I've never had before haha.

Looking for something else?

Not the answer you are looking for? Search for more explanations.