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Question
Answer the following:
Find (f ° g) (x) and (g ° f) (x)
f(x) = ex, g(x) = log x
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Solution
f(x) = ex, g(x) = log x
(f ° g) (x) = f[g(x)] = f(log x) = elogx = x ...[∵ alognm = m]
(g ° f) (x) = g[f(x)] = g[ex] = log ex = x log e = x ...[∵ loge e = 1]
∴ (f ° g) (x) = (g ° f) (x) = x
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