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# Mathematics Question Watch

1. Compute: Lim(x tends to infinity) x^3-x+2/-2x^3+x^2-1 ?
2. (Original post by ersdfrtg)
Compute: Lim(x tends to infinity) x^3-x+2/-2x^3+x^2-1 ?
Assuming it is then just divide top and bottom by the highest degree of and observe what happens to each term with x tending to infinity before evaluating what happens with the overall fraction.
3. (Original post by RDKGames)
Assuming it is then just divide top and bottom by the highest degree of and observe what happens to each term with x tending to infinity before evaluating what happens with the overall fraction.
And how would you divide this function by the highest degree of x? I tried doing long division, but it didn't work for me :/
4. (Original post by ersdfrtg)
And how would you divide this function by the highest degree of x? I tried doing long division, but it didn't work for me :/
The highest degree of x in this expression is 3 so divide top and bottom of this fraction by .
5. (Original post by notnek)
The highest degree of x in this expression is 3 so divide top and bottom of this fraction by .
But then that will give me negative powers: 1-x^-2+2x^-3 / -2+x^-2-x^-3
?
6. (Original post by ersdfrtg)
But then that will give me negative powers: 1-x^-2+2x^-3 / -2+x^-2-x^-3
?
It should be x^-1 instead of x^-2 on the bottom but other than that it's correct. Then the fraction can be written as

Go through each term in this fraction and think about what happens as

e.g. As , tends to 0.
7. x^3-x+2/-2x^3+x^2-1 ---> inf as x ---> inf

Do they not teach brackets anymore?
8. (Original post by mik1a)
x^3-x+2/-2x^3+x^2-1 ---> inf as x ---> inf

No it doesn't.
9. (Original post by RDKGames)
No it doesn't.
It does if you interpret brackets correctly. The x^3 is the dominant term.
10. (Original post by mik1a)
It does if you interpret brackets correctly. The x^3 is the dominant term.
Are you interpreting it as ? In which case that would be correct, otherwise I do not know what brackets you're talking about.
11. Yes, hence "do they not teach brackets anymore?"

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