# How do I find log 10?

Apr 24, 2015

That depends on what log 10 means. Do you want to find the log10 of 10, or do you want to find the log10 of another number?

To find the log "x" of a number, you're basically saying "What number will I have to raise "x" to the power of in order to get my number? Let's say you're finding the log10 of 100,000. You're asking "What will I have to put above that 10 to make it 100,000? The answer is 5, since 10^5 =100,000.

However, if you just need to find the log of 10, then log refers to log10 (just as a radical with no subscript before it indicates it is a square root). log10 of 10 is just 1.

Apr 26, 2015

I assume that you are using $\log$ for the Common logarithm, that is, for the logarithm base 10. (Many -- including WolframAlpha -- use $\log$ for the natural logarithm, so in case of confusion, ask.)

The general property of logarithms is that ${\log}_{b} b = 1$

This is because the log base $b$ of a number is the exponent need on $b$ to get the number. What exponent do we need on $b$ to get $B$/? !, of course.

So $\log 10 = {\log}_{10} 10 = 1$

If you meant to find the natural log of 10 ($\ln 10$) I'm sorry I misunderstood.
Please post again and someone will get you the approximation formula for $\ln x$.