Question
Show that f(x) = (x - 1)ex + 1 is an increasing function for all x > 0.

Answer

f(x) = (x - 1)ex + 1

f'(x) = (x - 1)ex + ex

= xex - ex + ex

= xex

Given: x > 0

We know,

ex > 0

⇒ xex > 0

⇒ f'(x) > 0, for all x > 0

So, f(x) is increasing on for all x > 0.

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