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If-f-x-2x-5-g-x-x-2-1-find-f-1-g-1-x-




Question Number 113904 by bobhans last updated on 16/Sep/20
If  { ((f(x)=(√(2x−5)))),((g(x)=x^2 +1)) :}  find (f^(−1) ○g)^(−1) (x)
$${If}\:\begin{cases}{{f}\left({x}\right)=\sqrt{\mathrm{2}{x}−\mathrm{5}}}\\{{g}\left({x}\right)={x}^{\mathrm{2}} +\mathrm{1}}\end{cases} \\ $$$${find}\:\left({f}^{−\mathrm{1}} \circ{g}\right)^{−\mathrm{1}} \left({x}\right) \\ $$
Answered by bemath last updated on 16/Sep/20
solution :   (f^(−1) ○g)^(−1) (x)=(g^(−1) ○f)(x)  and g^(−1) (x)=±(√(x−1))  then (g^(−1) ○f)(x)=±(√((√(2x−5))−1))
$${solution}\::\: \\ $$$$\left({f}^{−\mathrm{1}} \circ{g}\right)^{−\mathrm{1}} \left({x}\right)=\left({g}^{−\mathrm{1}} \circ{f}\right)\left({x}\right) \\ $$$${and}\:{g}^{−\mathrm{1}} \left({x}\right)=\pm\sqrt{{x}−\mathrm{1}} \\ $$$${then}\:\left({g}^{−\mathrm{1}} \circ{f}\right)\left({x}\right)=\pm\sqrt{\sqrt{\mathrm{2}{x}−\mathrm{5}}−\mathrm{1}} \\ $$

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