Exercise 1.3

Consider f : R+ → [4, ∞) given by f(x) = x2 + 4. Show that f is invertible with the inverse f–1 of f given by f–1(y) = √???? − ???? , where R+ is the set of all non-negative real numbers.

solution: Think about f : R+ → [4, ∞) given by f(x) = x2 + 4 Let x, y ∈ R → [4, ∞) then, at that point f(x) = x2 + 4 and f(y) = y2 + 4 on the off chance that f(x) = f(y) x2 + 4 = y2 + 4 or x = y f...

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