1.

यदि `x+1/x=3` तो `x^(5)+1/(x^(5))` का मान बताइए-A. 123B. 110C. 132D. 122

Answer» Correct Answer - A::C
`x+1/x=3`
(Cube both sides)
Formula:
`x^(5)+1/(x^(5))=(x^(3)+1/(x^(3)))(x^(2)+1/(x^(2))-(x+1/x)`
`x^(3)+1/(x^(3))+3x xx1/x(x+1/x)=27`
`x^(3)+1/(x^(3))=18`
`x+1/x=3` (squaring both sides)
`x^(2)+1/(x^(2))+2xx x xx1/x=9`
`x^(2)+1/(x^(2))=7`
Put in formula,
`x^(5)+1/(x^(5))=18xx7-3=123`


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