For a suitably chosen real constant a, let a function, f:R - - a → R be defined by f(x) = (a - x)/(a + x). Further suppose that for any real number x ≠ - a and f(x) ≠ - a, (fof)(x) = x. Then f(- 1/2) is equal to:

Sets, Relations and Functions: JEE Main 2020 Mathematics question

JEE Main 2020 · 6 Sep, Evening shift · Q3821

JEE Main 20206 Sep, Evening shiftMathematicsMediumSets, Relations and Functions168× since 2002

For a suitably chosen real constant a, let a function,

f:R - \left\{ { - a} \right\} \to R

be defined by

f(x) = {{a - x} \over {a + x}}

. Further suppose that for any real number

x \ne - a

and

f(x) \ne - a

, (fof)(x) = x. Then

f\left( { - {1 \over 2}} \right)

is equal to :