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Question -

Show that the function x2┬атАУ x + 1 is neither increasing nor decreasing on (0, 1).



Answer -

Given f(x) = x2┬атАУ x + 1

Now by differentiating the given equation with respect to x, weget

тЗТ┬а

тЗТ┬аfтАЩ(x)= 2x тАУ 1

Taking different region from (0, 1)

Let x тИИ (0, ┬╜)

тЗТ┬а2xтАУ 1 < 0

тЗТ┬аfтАЩ(x)< 0

Thus f(x) is decreasing in (0, ┬╜)

Let x тИИ (┬╜, 1)

тЗТ┬а2xтАУ 1 > 0

тЗТ┬аfтАЩ(x)> 0

Thus f(x) is increasing in (┬╜, 1)

Therefore, from above condition we find that

тЗТ┬аf(x) is decreasing in┬а(0, ┬╜) ┬аand increasing in┬а(┬╜, 1)

Hence, condition for f(x) neither increasing nor decreasing in(0, 1)

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