Find the interval in which function f(x) = x2 – 4x + 5 is increasing
Correct Answer :
(2, ∞)
Solution :
The correct option is (2, ∞).
To find the interval in which the quadratic function
is increasing, we need to determine where its first derivative is strictly positive, i.e., .
Step 1: Find the derivative of the function
We apply the power rule of differentiation to each term of the function:
Step 2: Set up the inequality for an increasing function
A function is increasing on an interval where its derivative is positive:
Substituting the derivative we found:
Step 3: Solve the inequality for x
Add 4 to both sides of the inequality:
Divide both sides by 2:
Conclusion:
Since , the function is increasing on the interval from 2 to infinity, which is represented in interval notation as (2, ∞).
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