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Answer the following: Solve : log2x4+4log42x = 2 - Mathematics and Statistics

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Question

Answer the following:

Solve : `sqrt(log_2 x^4) + 4log_4 sqrt(2/x)` = 2

Sum

Solution

`sqrt(log_2 x^4) + 4log_4 sqrt(2/x)` = 2

∴ `sqrt(4log_2x) + (4log_2(sqrt(2/x)))/log_2 4` = 2

∴ `2sqrt(log_2x) + (4 xx 1/2log_2 (2/x))/(2log_2 2)` = 2

∴ `2sqrt(log_2x) + log_2 (2/x)` = 2   ...[∵ log22 = 1]

∴ `2sqrt(log_2x) + log_2 2 - log_2 x` = 2

∴ `2sqrt(log_2 x) + 1 - log_2 x` = 2

∴ `2sqrt(log_2 x)` = 1 + log2x

Squaring both sides, we get,

4 log2x = (1 + log2x)2

∴ 4 log2x = 1 + 2log2x + (log2x)2

∴ (log2x)2 – 2log2x + 1 = 0

∴ (log2x – 1)2 = 0

∴ log2x – 1 = 0

∴ log2x = 1 = log22

∴ x = 2.

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Chapter 6: Functions - Miscellaneous Exercise 6.2 [Page 131]

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