lol I don't learn that till like the beginning of 2nd semester. Or maybe the end of first semester.

Doesn't matter if you haven't learned it yet. That's how you should do it. Read and understand the proof on Wikipedia; it's very straightforward.

Why are they giving you this question if you haven't learned L'Hopital yet?

Maybe so they all waste a bunch of time trying to solve it and after it's due the teacher can be like, "let me show you this cool trick."

The thing is, I can't do it that way on the test Thursday. So I have to know how to do it the long way if I want to get it right.

@abge: Lol that happened with derivatives in the last chapter of pre-cal.

Honestly, I have no idea how to do this without L'Hôpital because it is undefined. That's the entire point. You should just ask your teacher tomorrow.

Wait a second, is this problem impossible without L'hospital?

Ah, I see

I don't know why this problem is on the worksheet then. We're on chapter 1, and looking at my book L'hospital is chapter 7.

Oh, I'm sure it's possible, but it's probably a pain in the ass.

Because math books aren't perfect. They're usually made by grad students who really don't care, especially HS calc books. They probably just made a random problem and were like "just L'Hôpital it; everyone can do that".

CM, you can do this without L'Hospital. You were right to multiply top and bottom by the conjugate. That will give you:

(x - 1)(sqrt(x^2 + 3) + 2) / (x^2 + 3 - 4) = (x - 1) (sqrt(x^2 + 3) + 2) / (x^2 - 1)

Now factor the bottom. You get

(x - 1) (sqrt(x^2 + 3) + 2) / [(x + 1)(x - 1)]

Cancel the x - 1. You get

(sqrt(x^2 + 3) + 2) / (x + 1).

You can now direct substitute. You get 4 / 2 = 2.

No, algebra is cheating.

"Maybe so they all waste a bunch of time trying to solve it and after it's due the teacher can be like, "let me show you this cool trick.""

That's sadistic.

C-Man, put down the pencil and close your book now. Go see a movie, go to the mall, play a video game, watch porn, or phone a friend. Whatever will make you happy. Unless you're looking to a career in the sciences, you will NEVER need to know this crap in the real world. Don't waste your time on this. Life is short.

@Tolstoy: Well, I want to be a physicist, so yeah....

Nevermind then. I hope you will learn how to have fun with a long series of sadistic math teachers quicker than I did.

Still, I don't think you should waste your time trying to figure out something you haven't been taught yet (probably just to provide entertainment to someone who is probably getting off on your frustration).

@CM, Tolstoy is recommending that you intentionally fail Calculus to stick it to the man. Given that this is coming from a notorious conspiracy theorist, I advise you to heed his advice at your own risk.

@Tolstoy, is it really a good idea to tell CM to go watch porn, given his history?

ghug, my interest in this is not to 'stick it to the man', but to see that CM enjoys a happy life free from stressing over pointless advanced mathematical trivia that the vast majority of people never need to use. And if you read carefully, you will see that I suggested he listen to me only if he didn't plan on pursuing a career in the hard sciences (which, it turns out, he is).

For myself, I have been out of college for more than ten years and have not yet had a use for anything I studied in the Precalc class I was required to take (and paid for the privilege). The most complicated math I've found myself having to use as a network engineer and business owner is basic algebra. Trigonometry (which I studied in high school but forgot from lack of use) would have been fun to use in a literal handful unimportant events in life, but has proved to be far from the necessity that parents and teachers tried to convince me it was.

There is such a thing as being over-educated, and spending hundreds of hours and thousands of dollars to learn things that do not interest you and will have no real application in your life is a waste of both time and money. Since both are scarce, I only urge everyone to spend them wisely - weighing carefully the course you expect your life to take.

Tolstoy,

You're a US citizen right? It's a great country and all, but I don't think any US citizen should have to be overly concerned with his fellow countrymen being "over-educated".

Conservative dude, I wish you good luck with that algebra. Do your best, math can be very satisfying once you master it well.

Or you could just take calculus in high school - that way it's free.

Check out justmathtutoring on you tube. His videos are awesome

sorry it is patrickjmt