MCQ
If $f(x) = {x^2} + 1$, then $fof(x)$ is equal to
  • A
    ${x^2} + 1$
  • B
    ${x^2} + 2x + 2$
  • ${x^4} + 2{x^2} + 2$
  • D
    None of these

Answer

Correct option: C.
${x^4} + 2{x^2} + 2$
c
(c) $fof\,(x) = f\{ f(x)\} = {({x^2} + 1)^2} + 1 = {x^4} + 2{x^2} + 2.$

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