Mathematics

Mathematics

Problem

Given f:x→3x+6f : x \rightarrow 3x + 6 and h:x→x3h : x \rightarrow \frac{x}{3} , show that (f−1∘h−1)(x)=(h∘f)−1(x)(f^{-1} \circ h^{-1})(x) = (h \circ f)^{-1}(x) .
Intuitive explanation

The key insight is that function composition and inverses follow a reversal rule: the inverse of a composition flips the order. Rather than computing both sides separately, recognize that (h∘f)−1(h \circ f)^{-1} should equal f−1∘h−1f^{-1} \circ h^{-1} by the composition-reversal property. Your job is to find each function's inverse, apply them in the correct order on the left side, then compose hh and ff and invert that result on the right side—both should give you the same expression, confirming the rule works here.

Intuitive explanation

The key insight is that function composition and inverses follow a reversal rule: the inverse of a composition flips the order. Rather than computing both sides separately, recognize that (h∘f)−1(h \circ f)^{-1} should equal f−1∘h−1f^{-1} \circ h^{-1} by the composition-reversal property. Your job is to find each function's inverse, apply them in the correct order on the left side, then compose hh and ff and invert that result on the right side—both should give you the same expression, confirming the rule works here.

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