# Determining the order of a function with big Oh

1. May 11, 2010

### ZERO_COOL

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

Give the order of the following functions,

1. Ta(n) = 20^2 + (n + 4)^3

2. Tb(n) = (6n + 4)^2 + 3nlog2(n)

3. Tc(n) = (7n + 1)^2log10(n)

2. Relevant equations

3. The attempt at a solution

I got the following orders:-

1. Θ(n^3)

2. Θ(n^2)

3. Θ(n^2log10(n))

Number 2 is the most effecient for very large values of n because it is higher up the Big Oh ranking table.

Last edited: May 11, 2010
2. May 11, 2010

### Staff: Mentor

Do you have a question?

3. May 11, 2010

### phyzmatix

Looks ok to me.

EDIT: HAHAHA!!! Seems as if we're going for exactly the same threads tonight Mark!

Last edited: May 11, 2010
4. May 11, 2010

### ZERO_COOL

Yep LOL,

I was hoping someone could verify my answers, the brackets have me doubting my answers and I'm a bit dubious about my response to the third one.

5. May 11, 2010

### Staff: Mentor

I don't see anything wrong with any of them.

6. May 11, 2010

### ZERO_COOL

Thanks Mark and phyzmatix.

I was about 80% confident in my answers now I'm 100% :)