# Please help finding limit (does exist. =1/48)

1. Aug 27, 2014

### jog511

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

limx->64 (x^1/3 - 4)/(x - 64)

2. Relevant equations

3. The attempt at a solution
(64^1/3 -4)/(64 - 64) = 0/0 = not defined
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Aug 27, 2014

### dirk_mec1

Take the derative of f(x) = x^1/3 -4 at x = 64.

3. Aug 27, 2014

### LCKurtz

Or factor $x-64$ as the difference of two cubes.

4. Aug 27, 2014

### jog511

Thanks. I am trying to help my daughter with AP calculus. The problem states to find the limit algebraically so I cannot take the derivative.

5. Aug 27, 2014

### dextercioby

LC Kurtz gave you the hint: use the decomposition a3-b3

6. Aug 27, 2014

### jog511

We got it. Thanks a lot you guys

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