GATE 2021 IN – Question 33
The minimum of $f(x)=-x^2+10x+100$ on $[5,10]$ is ______.
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Correct answer: 100 to 100
Explanation
f′(x)=10−2x≤0 for x≥5, so f decreases across the interval and its minimum is at x=10. Alternatively compare endpoints of the concave parabola: f(5)=125 and f(10)=100. The minimum is **100**.