# Length of a curve

1. Nov 1, 2009

### Mugen Prospec

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

3ti+ 8t$$^{(3/2)}$$j + 12t$$^{2}$$k

0 $$\leq$$ t $$\leq$$ 1

2. Relevant equations

3. The attempt at a solution
I thought you are supposed to take the derivative of all three then square that. those all go into the length formula

My book says answer should be 15 but Im not doing something right. my test is tomorrow, can some one give me a walk through for this one.

2. Nov 1, 2009

### Staff: Mentor

I get 15. For this problem, the quantity under the radical is a perfect square quadratic. Try factoring the quadratic before taking the square root.

3. Nov 1, 2009

### Mugen Prospec

ok I think i got it. thank you