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The minimum value of x logex is equal to : 

A. e 

B. \(\frac{1}{e}\)

C.\(-\frac{1}{e}\)

D. 2e

1 Answer

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Best answer

Option : (C)

f(x) = x logex

Differentiating f(x) with respect to x, we get

f'(x) = x \(\times\) \(\frac{1}{x}\)+ loge\(\times\)1

= 1 + logex

Differentiating f’(x) with respect to x, we get

f"(x) = \(\frac{1}{x}\)

For minima at x = c, 

f’(c) = 0 and f’’(c) > 0

f’(x) = 0 

⇒ x = \(\frac{1}{e}\)

f"(\(\frac{1}{e}\)) = e > 0

Hence,

x = \(\frac{1}{e}\) is a point of minima for f(x) and f(\(\frac{1}{e}\)) = \(-\frac{1}{e}\) is the minimum value of f(x).

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