Let ƒ : R $\to$ R be such that for all
x $\in$ R
(21+x + 21–x), ƒ(x) and (3x + 3–x) are in
A.P.,
then the minimum value of ƒ(x) is
Solution
f(x) = $${{2\left( {{2^x} + {2^{ - x}}} \right) + \left( {{3^x} + {3^{ - x}}} \right)} \over 2} \ge 3$$
<br><br>As we know, A.M > G.M
About this question
Subject: Mathematics · Chapter: Sequences and Series · Topic: Arithmetic Progression
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