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Question

The value of \({4^{2{{\log }}3}}\) is

The correct answer is

4

Logarithm Calculation: Unveiling the Value of \(4^{2{{\log }}3}\)

To find the value of the expression \({4^{2{{\log }}3}}\), we need to use fundamental properties of logarithms and exponents. The expression involves an exponential term where the exponent itself contains a logarithm.

Understanding Logarithm Properties

Two essential logarithm properties are crucial for solving this problem:

  • Power Rule of Logarithms: The property states that the logarithm of a number raised to an exponent is the exponent times the logarithm of the number. Mathematically, this is expressed as: \[ \text{n} \log_b \text{x} = \log_b (\text{x}^\text{n}) \]
  • Base-Exponent Identity: This property is very useful when the base of an exponential term matches the base of the logarithm in its exponent. It states: \[ a^{\log_a x} = x \]

Simplifying the Expression \(4^{2{{\log }}3}\)

Let's apply the first property to the exponent of our expression \({4^{2{{\log }}3}}\). The exponent is \(2{{\log }}3\). Here, \(n=2\) and \(x=3\). Applying the power rule:

\[ 2{{\log }}3 = {{\log }}3^2 \]

Now, calculate the value of \(3^2\):

\[ 3^2 = 9 \]

Substitute this back into our expression:

\[ {4^{2{{\log }}3}} = {4^{{{\log }}9}} \]

At this point, the base of the logarithm is not explicitly stated. In many mathematical contexts, if the base is not specified, it could imply a common logarithm (base 10) or a natural logarithm (base 'e'). However, given the multiple-choice options are simple integers, it is highly probable that the base of the logarithm is intended to simplify the expression to one of these integer values using the Base-Exponent Identity property.

For the expression \({4^{{{\log }}9}}\) to simplify using the property \(a^{\log_a x} = x\), the base of the logarithm must be such that it allows simplification with the base 4.

Let's assume the base of the logarithm is \(b\). Our expression is \({4^{{{\log }_b}9}}\). For this to simplify to an integer option, we consider the scenario where the logarithm's base \(b\) is related to 9 in such a way that the entire expression simplifies nicely. If the base \(b\) of the logarithm is \(9\), then we can apply the second property directly.

Assuming the base of the logarithm is \(9\):

\[ {4^{{{\log }_9}9}} \]

Final Calculation

Now, using the Base-Exponent Identity property \(a^{\log_a x} = x\), where \(a=9\) and \(x=9\) for the logarithm part \({{\log }_9}9\):

\[ {{\log }_9}9 = 1 \]

Substitute this value back into the expression:

\[ {4^{{{\log }_9}9}} = 4^1 \]

Finally, calculate \(4^1\):

\[ 4^1 = 4 \]

Therefore, the value of \({4^{2{{\log }}3}}\) is \(4\) when the logarithm is considered to have a base of \(9\).

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Important Questions from Mathematical Logic

  1. Which of the following equation represents a function?

  2. If \(\sqrt {1 + \frac{x}{{225}}} = \frac{{17}}{{15}}\) , then the value of x is

  3. If \(x = 7 - 4\sqrt 3 \) then the value of \(x + \frac{1}{x}\) is

  4. \(\sqrt[3]{{\sqrt {0.000729} }} =\)
  5. Which set does not represent the sides of a right angled triangle?

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