1.

The set of real values of x for which `2^("log"_(sqrt(2))(x-1)) gt x+ 5,` isA. `(-oo, -1) cup (4, oo)`B. `(4, oo)`C. `(-1, 4)`D. none of these

Answer» Correct Answer - B
We have ,
`2^("log"_(sqrt(2))(x-1)) gt x+ 5`
`rArr 2^(2"log"2 (x-1)) gt x+ 5`
`rArr (x-1)^(2) gt x+ 5`
`rArr x^(2) -3x-4 gt 0`
`rArr (x-4)(x+1) gt 0`
`rArr x lt -1 "or" x gt 4`
`rArr x gt 4 " " [because "log"_(sqrt(2))(x-1) " is defined for " (x-1) gt 0]`
`rArr x in (4, oo)`


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