1.

`x^((log)_5x)>5`implies`x in (0,oo)`(b) [2,2.5] (c)(2,2.5) (d) (0,2.5)A. ` x in (0, infty)`B. ` x in (0, 1//5) cup (5, infty)`C. ` x in (1, infty)`D. ` x in (1, 2)`

Answer» Correct Answer - B
`x^(log_(5) x) gt 5`
Taking logarithm with base 5, we have
`(log_(5)x) (log_(5)x) gt 1`
` or (log_(5)x-1) (log_(5)x+1) gt 0`
` or log_(5) x gt 1 or log_(5) x lt - 1`
`rArr x gt 5 or x lt 1//5`
Also we must have ` x gt 0` . Thus,
` x in (0, 1//5) cup (5, infty)`.


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