Quick Math Problem? Calc

[eamon]

Might post a few more questions in a little bit, but just trying to review for a test and I was wondering if someone could explain the steps in solving this specific equation:

Find the limit of the function as X---> approaches 2

((X^3)-8)/(X-2)

I'm not too sure on how to factor this problem into a simpler form in order to plug x=2 into the equation to achieve a working answer.
For reference the answer, f(x), is equal to 12.
I got it once, but I forgot how

Thanks in advance.

[Freakazoid]

too lazy to do the math myself soooo

you have a difference of cubes on top. factor it.

(x-2)(x^2+2x+4) / (x-2)

cancel out equal factors

= x^2+2x+4

[eamon]

Originally Posted by Freakazoid

too lazy to do the math myself soooo

you have a difference of cubes on top. factor it.

(x-2)(x^2+2x+4) / (x-2)

cancel out equal factors

= x^2+2x+4

How do you get from the first one to that.
That's what I'm stumped on
Thanks for input

[Freakazoid]

Originally Posted by eamon

How do you get from the first one to that.
That's what I'm stumped on
Thanks for input

not to be a jackass (I promise), but THAT one you should really know if you're taking calc? But as a refresher:

a3 + b3 = (a + b)(a² − ab + b²)


obviously x=a and b=-2 in this example

[Greenkirby21]

wolframalpha.com

shows u the steps as well

http://www.wolframalpha.com/input/?i...29%2F%28X-2%29

[Forcefed3]

Originally Posted by Greenkirby21

wolframalpha.com

shows u the steps as well

http://www.wolframalpha.com/input/?i...29%2F%28X-2%29

[Brey335i]

Find the limit of the function as X---> approaches 2

((X^3)-8)/(X-2)

Plug in 2 and you get 0/0. Let me introduce you to the concept of L'Hospital's Rule.

Find the derivative of the top and the bottom:

((x^3)-8) / (x-2) becomes (3x^2) / 1. Now plug in 2. And you get 12.

If you haven't been introduced to LHR or derivatives then just ignore my answer...

[eamon]

Originally Posted by Greenkirby21

wolframalpha.com

shows u the steps as well

http://www.wolframalpha.com/input/?i...29%2F%28X-2%29

Originally Posted by Freakazoid

not to be a jackass (I promise), but THAT one you should really know if you're taking calc? But as a refresher:

a3 + b3 = (a + b)(a² − ab + b²)


obviously x=a and b=-2 in this example

Thanks guys

[eamon]

Originally Posted by Brey335i

Find the limit of the function as X---> approaches 2

((X^3)-8)/(X-2)

Plug in 2 and you get 0/0. Let me introduce you to the concept of L'Hospital's Rule.

Find the derivative of the top and the bottom:

((x^3)-8) / (x-2) becomes (3x^2) / 1. Now plug in 2. And you get 12.

If you haven't been introduced to LHR or derivatives then just ignore my answer...

LOL sounds good.
Have no idea how you got that.
Guess I'll find out later on.

[Greenkirby21]

Originally Posted by eamon

LOL sounds good.
Have no idea how you got that.
Guess I'll find out later on.

i notice your in dallas too . what university do you go to?

Anyways, in calc, its pretty hard in the beginning, but the teachers just troll you. You learn how to do everything the hard way, then they teach you a new rule that just destroys everything, as seen by the fellow member who used l'hopitals rule. You will learn it later, and makes solving those problems a whole lot easier

[c_jeong89]

L'Hospital's rule ftw.

[eamon]

Originally Posted by Greenkirby21

i notice your in dallas too . what university do you go to?

Anyways, in calc, its pretty hard in the beginning, but the teachers just troll you. You learn how to do everything the hard way, then they teach you a new rule that just destroys everything, as seen by the fellow member who used l'hopitals rule. You will learn it later, and makes solving those problems a whole lot easier

Gotta love school
I'm actually a senior in high school
Just taking a couple semesters of AP Calc and Physics to get credit, if not I'll at least have some experience.
Hopefully will make it into Baylor or A&M for the next school year

[BayMoWe335]

This brings back memories. Lord, I'm so glad I'm not in school anymore. After differential equations, I was done with math forever.

Props for doing this crap without going insane. This isn't hard, but math can really blow ass.

[Greenkirby21]

Originally Posted by BayMoWe335

This brings back memories. Lord, I'm so glad I'm not in school anymore. After differential equations, I was done with math forever.

Props for doing this crap without going insane. This isn't hard, but math can really blow ass.

Ahh Diff EQ : )

I am taking automata theory right now, don't even know what the shit is about still : |

[-=Hot|Ice=-]

Taking Applied Calc. I think it's called MA 155. Feel like my brain is going to explode.

[Want]

Use L'Hopital's rule. google it. very easy.

[dth656]

Originally Posted by eamon

Gotta love school
I'm actually a senior in high school
Just taking a couple semesters of AP Calc and Physics to get credit, if not I'll at least have some experience.
Hopefully will make it into Baylor or A&M for the next school year

i went to HS in houston, and took AP calc, bio, english, etc. as long as you have above a certain SAT and class rank (the bar used to be super low if if i recall), you should get a pre-filled application for aTm and UT. all you have to do is sign and send it in.

if you are taking AP classes, you are most likely at least top 15% of your class (in my school district, AP classes counted for extra grade points).