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Verify that f and g are inverse functions of each other, where f(x) = x3 + 4, g(x) = x-43

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Question

Verify that f and g are inverse functions of each other, where f(x) = x3 + 4, g(x) = `root(3)(x - 4)`

Sum
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Solution

f(x) = x3 + 4

Replacing x by g(x), we get

f[g(x)] = [g(x)]3 + 4

= `(root(3)(x - 4))^3 + 4`

= x – 4 + 4 

= x

g(x) = `root(3)(x - 4)`

Replacing x by f(x), we get

g[f(x)] = `root(3)("f"(x) - 4)`

= `root(3)(x^3 + 4 - 4)`

= `root(3)(x^3)`

= x

Since, f[g(x)] = x and g[f(x)] = x.

∴ f and g are inverse functions of each other.

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Chapter 6: Functions - Exercise 6.2 [Page 127]

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