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Question

Question: If $\log_{a} 3=2$ and $\log_{b} 8=3$ then $\log_{b} a$ is....

If loga3=2\log_{a} 3=2 and logb8=3\log_{b} 8=3 then logba\log_{b} a is.

Answer

\frac{1}{2} \log_{2} 3

Explanation

Solution

  1. Convert logarithmic form to exponential form:

    • From loga3=2\log_{a} 3 = 2, we get a2=3a^2 = 3. Since the base of a logarithm must be positive, a=3=31/2a = \sqrt{3} = 3^{1/2}.
    • From logb8=3\log_{b} 8 = 3, we get b3=8b^3 = 8. Taking the cube root, b=2b = 2.
  2. Substitute the values of aa and bb into logba\log_{b} a:

    • We need to find logba=log2(31/2)\log_{b} a = \log_{2} (3^{1/2}).
  3. Apply logarithm properties:

    • Using the power rule for logarithms, logx(yz)=zlogxy\log_x (y^z) = z \log_x y, we simplify: log2(31/2)=12log23\log_{2} (3^{1/2}) = \frac{1}{2} \log_{2} 3.

Therefore, logba=12log23\log_{b} a = \frac{1}{2} \log_{2} 3.