Math Problem Statement

Given log_a b = 4, find log_a (4 / sqrt(a^b)).

Solution

The problem you're presenting is a logarithmic expression. From the image, it appears you're given the equation logab=4\log_a b = 4 and are asked to determine the value of the following expression:

loga(4ab)\log_a \left( \frac{4}{\sqrt{a^b}} \right)

Let's break this down step by step.

Step 1: Understanding logab=4\log_a b = 4

This means that the logarithm of bb with base aa equals 4. We can express this as:

a4=ba^4 = b

Step 2: Analyzing the expression loga(4ab)\log_a \left( \frac{4}{\sqrt{a^b}} \right)

We need to evaluate:

loga(4ab)\log_a \left( \frac{4}{\sqrt{a^b}} \right)

First, let's rewrite ab\sqrt{a^b} as:

ab=ab2\sqrt{a^b} = a^{\frac{b}{2}}

Now, the expression becomes:

loga(4ab2)\log_a \left( \frac{4}{a^{\frac{b}{2}}} \right)

Step 3: Applying Logarithmic Properties

We use the logarithmic property loga(xy)=logaxlogay\log_a \left( \frac{x}{y} \right) = \log_a x - \log_a y:

loga(4ab2)=loga4loga(ab2)\log_a \left( \frac{4}{a^{\frac{b}{2}}} \right) = \log_a 4 - \log_a \left( a^{\frac{b}{2}} \right)

We know that loga(ax)=x\log_a \left( a^x \right) = x, so:

loga(ab2)=b2\log_a \left( a^{\frac{b}{2}} \right) = \frac{b}{2}

Thus, the expression simplifies to:

loga4b2\log_a 4 - \frac{b}{2}

Step 4: Substituting b=a4b = a^4

From Step 1, we know b=a4b = a^4, so we substitute this into the expression:

loga4a42\log_a 4 - \frac{a^4}{2}

So, the final result is:

loga4a42\log_a 4 - \frac{a^4}{2}

Would you like to see further details or have any questions about this solution?

Related Questions:

  1. How can we use logarithmic identities to simplify more complex expressions?
  2. What is the inverse of a logarithmic function, and how can it help in solving equations?
  3. How does the logarithm with an exponent work, and how do you simplify such expressions?
  4. What is the relationship between logarithms and exponential equations?
  5. Can you explain the steps in solving logarithmic equations with different bases?

Tip: When dealing with logarithmic expressions, always try to use basic properties of logarithms such as logb(xy)=logbx+logby\log_b \left( x \cdot y \right) = \log_b x + \log_b y and logb(xy)=logbxlogby\log_b \left( \frac{x}{y} \right) = \log_b x - \log_b y to break down complex terms into simpler components.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Exponents
Algebra

Formulas

log_a(x / y) = log_a x - log_a y
log_a(a^x) = x
sqrt(x) = x^(1/2)

Theorems

Properties of Logarithms

Suitable Grade Level

Grades 10-12