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How to express a two logarithm into a single logarithm

User Dan Gamble
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Answer:

There are different methods to express a two logarithm into a single logarithm, depending on the specific form of the logarithms involved. Here are some examples:

Logarithms with the same base:

If you have two logarithms with the same base, you can use the following logarithmic identity:

log_a(x) + log_a(y) = log_a(xy)

Using this identity, you can express a sum or difference of logarithms with the same base as a single logarithm:

Example 1: log_2(3) + log_2(5) = log_2(3*5) = log_2(15)

Example 2: log_5(7) - log_5(2) = log_5(7/2)

Logarithms with different bases:

If you have two logarithms with different bases, you can use the following change of base formula to express them with a common base:

log_a(x) = log_b(x) / log_b(a)

Using this formula, you can rewrite a logarithm with a base a as a logarithm with a base b:

Example 1: log_2(7) = log_10(7) / log_10(2)

Example 2: log_5(2) = log_2(2) / log_2(5)

Once you have expressed both logarithms with the same base, you can apply the logarithmic identity from method 1 to simplify them into a single logarithm.

User Roger Perkins
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