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The function f(x)=x2x+1f(x) = x^2 - x + 1 is

Solution

Correct Option: 2

Given the function f(x)=x2x+1f(x) = x^2 - x + 1

To find where the function is increasing or decreasing, find the derivative:

f(x)=2x1f'(x) = 2x - 1


Setting f(x)=0f'(x) = 0 to find the critical point:

2x1=02x - 1 = 0

2x=12x = 1

x=12x = \frac{1}{2}


For x<12x < \frac{1}{2}, test x=0x = 0:

f(0)=2(0)1=1f'(0) = 2(0) - 1 = -1

Since f(0)<0f'(0) < 0, the function is decreasing on (,12)(-\infty, \frac{1}{2})


For x>12x > \frac{1}{2}, test x=1x = 1:

f(1)=2(1)1=1f'(1) = 2(1) - 1 = 1

Since f(1)>0f'(1) > 0, the function is increasing on (12,)(\frac{1}{2}, \infty)


The function is:

Decreasing on (,12)(-\infty, \frac{1}{2})

Increasing on (12,)(\frac{1}{2}, \infty)

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