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Basic of Logarithms
medium
If $n = 1983!$, then the value of expression $\frac{1}{{{{\log }_2}n}} + \frac{1}{{{{\log }_3}n}} + \frac{1}{{{{\log }_4}n}} + ....... + \frac{1}{{{{\log }_{1983}}n}}$ is equal to
A
$-1$
B
$0$
C
$1$
D
$2$
Solution
(c) $\frac{1}{{{{\log }_2}n}} + \frac{1}{{{{\log }_3}n}} + \frac{1}{{{{\log }_4}n}} + ……. + \frac{1}{{{{\log }_{1983}}n}}$
= ${\log _n}2 + {\log _n}3 + {\log _n}4 + …… + {\log _n}1983$
= ${\log _n}(2.3.4….1983) = {\log _n}(1983!) = {\log _n}n = 1$.
Standard 11
Mathematics