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For the function f(x)=1x2+2x+2f(x) = \frac{1}{x^2+2x+2}

which of the following statements are TRUE?

A. f(x)f(x) is increasing on (−∞,−1)(-\infty, -1)

B. f(x)f(x) is decreasing on (−∞,−1)(-\infty, -1)

C. f(x)f(x) is decreasing on (−1,∞)(-1, \infty)

D. maximum value of f(x)f(x) is 1

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

Write f(x)=1(x+1)2+1f(x)=\frac{1}{(x+1)^2+1}. The denominator decreases on (−∞,−1)(-\infty,-1) and increases on (−1,∞)(-1,\infty), so ff increases then decreases, with least denominator 11 at x=−1x=-1.

Thus A and C hold, B fails, and the maximum value is f(−1)=1f(-1)=1, so D holds.

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