Show that the Quotient Rule of Logarithms works for the base 4 expression  log464−log416 .

1 answer

The Quotient Rule of Logarithms states that for any logarithm \(\log_b(a) - \log_b(c)\), it can be rewritten as:

\[ \log_b\left(\frac{a}{c}\right) \]

In this case, we want to verify this for the expression \( \log_4(64) - \log_4(16) \).

First, we can apply the Quotient Rule:

\[ \log_4(64) - \log_4(16) = \log_4\left(\frac{64}{16}\right) \]

Now, let's calculate \(\frac{64}{16}\):

\[ \frac{64}{16} = 4 \]

Thus, we can rewrite the expression as:

\[ \log_4(64) - \log_4(16) = \log_4(4) \]

Now we can evaluate \(\log_4(4)\). Since \(4\) is equal to \(4^1\), we have:

\[ \log_4(4) = 1 \]

Next, we will directly compute \(\log_4(64)\) and \(\log_4(16)\) to confirm our calculation.

  1. Calculate \(\log_4(64)\):

Since \(64 = 4^3\), we have:

\[ \log_4(64) = \log_4(4^3) = 3 \]

  1. Calculate \(\log_4(16)\):

Since \(16 = 4^2\), we have:

\[ \log_4(16) = \log_4(4^2) = 2 \]

Now, we can compute \( \log_4(64) - \log_4(16) \):

\[ \log_4(64) - \log_4(16) = 3 - 2 = 1 \]

We have confirmed that both sides match:

\[ \log_4(64) - \log_4(16) = \log_4(4) = 1 \]

Thus, this shows that the Quotient Rule of Logarithms holds for the given expression:

\[ \log_4(64) - \log_4(16) = \log_4\left(\frac{64}{16}\right) \]

as expected.