Verifying Inverse Functions By Composition
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Let f(x)=x2 and g(x)=√x.
A.
Find h(x)=f(g(x)) and state its domain.
- h(x)=x, x≥0
- h(x)=|x|, ℝ
- h(x)=x, ℝ
- h(x)=|x|, x≤0
B.
Find h2(x)=g(f(x)) and state its domain.
- h2(x)=x, x≥0
- h2(x)=|x|, ℝ
- h2(x)=x, ℝ
- h2(x)=|x|, x≤0
C.
Is g(x) the inverse of f(x)? Explain.
- Yes, since both h(x) and h2(x) are equal to x.
- No, because the domain of h(x) and h2(x) are different.
- No, because h(x)≠x.
- No, because h2(x)≠x.
D.
When finding h(x), what is the importance of the domain?
- It has no special importance.
- It shows that, even though h(x) and h2(x) seem to be the same function, they have different domains.
- It is necessary to see that the domain is all real numbers because the domain of inverse functions, when composed with the original function, needs to be all real numbers.
- It means that the absolute value sign can be dropped, since the domain is zero and positive numbers, so the function simply becomes x.