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Question
If `"r" - (1)/"r" = 4`; find : `"r"^4 + (1)/"r"^4`
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Solution
`("r"^2 + 1/"r"^2)^2`
= `"r"^4 + (1)/sqrt(4) + 2`
⇒ (18)2 = `"r"^4 + (1)/"r"^4 + 2`
⇒ `"r"^4 + (1)/"r"^4`
= 324 - 2
= 322.
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