1.

Let `A=(x in R: x ge 1)`. The inverse of the function of `f:A to A` given by `f(x)=2^(x^((x-1))`. IsA. `((1)/(2))^(x^((x-1)))`B. `(1)/(2){1+sqrt(1+4log_(2)x)}`C. `(1)/(2){1-sqrt(1+4log_(2)x)}`D. None of these

Answer» Correct Answer - B
It can be easily verified that `f:A to A` is a bijection.
`"Let"f(x)=y"Then"`
`f(x)=y`
`Rightarrow 2^(x^((x-1)))=y``Rightarrow x(x-1)=log_(2)y`
`Rightarrow x^(2)-x-log_(2) y=0`
`x=(1pmsqrt(1+4log_(2)y))/(2)`
`Rightarrow x=(1)/(2) [1+sqrt(1+4log_(2)y)]" "[therefore x lt 1]`
`Rightarrow f^(-1)(y)=(1)/(2){1+sqrt(1+4log_(2)y)}`
`Rightarrow f^(-1)(y)=(1)/(2){1+sqrt(1+4log_(2)y)}`
x`f^(-1)(x)=(1)/(2) {1+sqrt(1+4log_(2) x)}`


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