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Question

Question: How do you evaluate\[{{\log }_{16}}\left( 8 \right)\]?...

How do you evaluatelog16(8){{\log }_{16}}\left( 8 \right)?

Explanation

Solution

These types of problems can be solved by considering the solution as any variable. Then consider the equation as equation (1). Now we have to apply the basic logarithm formula and then apply this formula to equation (1). Now, by applying some exponential formulas we will get the solution of the problem.

Complete step-by-step solution:
From the given question, we are given to solve log16(8){{\log }_{16}}\left( 8 \right).
Let us assume the given solution as N.
log16(8)=N{{\log }_{16}}\left( 8 \right)=N.
Let us consider
log16(8)=N.......(1){{\log }_{16}}\left( 8 \right)=N.......\left( 1 \right)
As we know that
if logaN=x;{{\log }_{a}}N=x; then ax=N{{a}^{x}}=N
Now we have to apply the above concept to the equation (1).
By applying the above concept, we get
16N=8{{16}^{N}}=8.
Let us consider this as equation (2).
16N=8.......(2){{16}^{N}}=8.......\left( 2 \right)
Now we have to evaluate the above equation and we have to find the value of N.
We can write 1616as24{{2}^{4}}.So, now substitute this in equation (2).
By the formula
(am)n=amn{{\left( {{a}^{m}} \right)}^{n}}={{a}^{mn}}.
Now we have to apply the above concept to the equation (3).
24N=8........(4){{2}^{4N}}=8........\left( 4 \right)
We can write 8 as 23{{2}^{3}}.
Now making 8 as 23{{2}^{3}} we will get
24N=23.....(5){{2}^{4N}}={{2}^{3}}.....\left( 5 \right)
By the formula

& if\text{ }{{a}^{m}}={{a}^{n}} \\\ & then\text{ }m=n \\\ \end{aligned}$$ By applying the above concept to the equation (5), we get $$\begin{aligned} & 4N=3 \\\ & N=\dfrac{3}{4} \\\ \end{aligned}$$$$$$ **So, we obtain the value of N. So it is clear that by solving the equation $${{\log }_{16}}\left( 8 \right)$$, we get $$N=\dfrac{3}{4}$$ ** **Note:** Some students may have a misconception that if $${{\log }_{a}}N=x;$$ then $${{a}^{x}}=N$$ .But we know that if $${{\log }_{a}}N=x;$$ then $${{a}^{x}}=N$$ . If this misconception is followed, then the final answer may get interrupted. So, these misconceptions should be avoided. Also students should avoid calculation mistakes while solving the problem.