The function is defined by and by

MATHEMATICS · Single correct · CBSE · Mathematics · Relations and Functions · Relations and Functions

Problem

The function f:[2,∞)→[0,∞)f:[2,\infty)\to[0,\infty) is defined by f(x)=x−2f(x)=\sqrt{x-2} and g:[0,∞)→[2,∞)g:[0,\infty)\to[2,\infty) by g(x)=x2+2g(x)=x^{2}+2. Which of the following describes the relationship between ff and gg? (a) f∘g=I[0,∞)f\circ g=I_{[0,\infty)} but g∘f≠I[2,∞)g\circ f\neq I_{[2,\infty)}, so they are not mutual inverses (b) g∘f=I[2,∞)g\circ f=I_{[2,\infty)} but f∘g≠I[0,∞)f\circ g\neq I_{[0,\infty)}, so they are not mutual inverses (c) f∘g=I[0,∞)f\circ g=I_{[0,\infty)} and g∘f=I[2,∞)g\circ f=I_{[2,\infty)}, so they are mutual inverses (d) Neither composition equals the identity on its domain

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