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Log1/6(5). I am absolutely clueless as to what i'm supposed to do. The 1/6 is below the log.

1 Answer

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Question: Evaluate/death stare at
log_{\frac{1}6}(5).

Let's talk about what logarithms mean.

Suppose
log_{\frac{1}6}(5)=x.

That's the same thing as
5=(\frac{1}6)^x. It's just been simplified.
(Logarithms are the inverse operations of exponents)

We can use a calculator to evaluate logarithms that are in base 10.
(In this case, the base is 1/6)

How can we change this so that it uses just base 10?
We can use something called the change-of-base formula.

Here's what the change of base formula looks like.


log_x(n)=(log_y(n))/(log_y(x))

In this case, we'll set the base
y to be 10. (you can set it to whatever you want)
x is going to be 1/6, and
n is 5.
When the base is 10, we don't have to write it, it's like a plus zero or a times one.


log_\frac{1}6(5)=\frac{log(5)}{log(\frac{1}6)}

Punch this into a calculator to find your answer.


\frac{log(5)}{log(\frac{1}6)} \approx \boxed{-0.8982444017}

You can always check your answer if you need to, of course.


(\frac{1}6)^(-0.8982444017) \approx 5
User Hamed Naeemaei
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