# Log base 2 key strokes.

1. Sep 14, 2007

### starchild75

1. The problem statement, all variables and given/known data
2^x=1500. solve for x. I need to know the key strokes on my scientific calculator. If I push log, it assumes log base 10. I need base 2.

2. Relevant equations

3. The attempt at a solution

2. Sep 14, 2007

### bob1182006

do you know of a formula that can be used to "change bases" for logs?

3. Sep 14, 2007

### starchild75

I don't recall it. Can you give it to me? Is there no way to find the log base 2 on a calculator?

4. Sep 14, 2007

### bob1182006

If i remember right it's
$$log_b a = \frac{log_k a}{log_k b}$$
Where k is the base you're going to. In this case it would be base 10 so just log in your calculator.

5. Sep 14, 2007

### starchild75

What do you put in place of a and b?

6. Sep 14, 2007

### starchild75

I got that to work. I figured it out. Thanks a lot. It just seemed like there was a way to figure that out on a calculator but I can't remember for sure.

Starchild