# Homework Help: I can't seem to find this limit

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1. Jan 9, 2016

### Lavender

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
I tried using the rule of multiplying with the "conjugate", for example what's above multiplied by (√n^3+3n)+(√n^3+2n^2+3)/(√n^3+3n)+(√n^3+2n^2+3).
But I'm left with a huge mess :(
I also tried dividing the top and the bottom by n^2 in the square roots to get the n out, but that didn't work either :(

2. Jan 9, 2016

### haruspex

The conjugate method looks good here. It doesn't give a mess in the numerator, right? In the denominator, do you need all the terms, or is it sufficient then only to look at the leading terms?

3. Jan 9, 2016

### Incand

The image is so bad I can't even see the value of the exponents, try to write it out in latex next time.
Assuming what you wrote is $\frac{\sqrt{n^3+3n}-\sqrt{n^3+2n^2+3}}{\sqrt{n+2}}$
multiplying with the conjugate works for me. After you done that note that only the "highest order" terms matter.

4. Jan 10, 2016

### vela

Staff Emeritus
After you multiply by the conjugate, you want to pull the highest power of n, not $n^2$, out of each of the square roots.