How does adding the log together automatically mean that it is a factorial?
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Answer: The answer is given below.
Step-by-step explanation: We are given an equality involving logarithm and we are to show the implication of L.H.S. to R.H.S.
We will be using the following two properties of logarithm:
[tex](i)~\log_ba=\dfrac{1}{\log_ab},\\\\\\(ii)~log_ab+\log_ac=\log_a(bc).[/tex]
The proof is as follows:
[tex]L.H.S.\\\\\\=\dfrac{1}{\log_2N}+\dfrac{1}{\log_3N}+\dfrac{1}{\log_4N}+\cdots+\dfrac{1}{\log_{100}N}\\\\\\=\log_N2+\logN3+\log_N4+\cdots+\log_N100\\\\=\log_N\{2.3.4...100\}\\\\=\log_N\{1.2.3.4...100\}\\\\=\log_N{100!}\\\\=\dfrac{1}{\log_{100!}N}\\\\=R.H.S.[/tex]
Hence proved.