Question
Question: How do you expand \[\log _{b}^{\sqrt{\dfrac{57}{74}}}\]?...
How do you expand logb7457?
Solution
From the question we are asked to find the logarithmic expansion of logb7457. So, for the questions of these kind we will use the basic logarithmic formulae which are logc(ba)=logca−logcb and logban=nlogba. Using the above-mentioned logarithmic formulae, we will simplify the question and get the solution for the required question.
Complete step by step solution:
Firstly, for the question logb7457 we will use the basic logarithmic formula which is logc(ba)=logca−logcb.
After using the formula, we will simplify the equation. So, the equation will be reduced as follows.
⇒logb7457
⇒logb7457=logb57−logb74
Here after getting the above equation for the further simplification we will use the formulae logban=nlogba to the equation.
Here, Before using the logarithmic formula logban=nlogba in the above equation.
First, we have to write the above equation in that form as logban
Now, we will rearrange the equation which we will get in the above form. We will arrange in the above to get the solution to look in a more familiar or an easier way.
So, after rearranging the equation will become as follows.
⇒logb7457=logb57−logb74
⇒logb7457=logb5721−logb7421
Now, we will apply the above formula logban=nlogba for the both the terms in right hand side.
By applying we will get,
⇒logb7457=21logb57−21logb74
Therefore, the solution to the given question will belogb7457=21logb57−21logb74.
Note: Students must have a very good knowledge in the concept of logarithms. Students should recall all the formulas of logarithms while doing this problem. We must know basic formulae like,
logc(ba)=logca−logcb,⇒ln(ab)=lna+lnb and logban=nlogba. Students should not make any calculation mistakes.