If a = x – x2 + x3 – x4 + x5 – x6 + … infinite terms and |x| < 1. Find x in terms of a.
Explanation:
Given, a = (x + x3 + x5 + …) – (x2 + x4 + x6 + …)
⇒ a = x1-x2 - x21-x2
⇒ a = x-x21-x2
⇒ a =x(1-x)(1+x)(1-x)
⇒ a = x(1+x)
⇒ a + ax = x
⇒ a = x(1 - a)
⇒ x = a/(1 - a)
Hence, option (a).
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