Question
Question: If f(x) = x<sup>2</sup> + ax + 1 is monotonic increasing in the interval [1, 2], then the minimum v...
If f(x) = x2 + ax + 1 is monotonic increasing in the interval
[1, 2], then the minimum value of a is –
A
– 1
B
– 2
C
1
D
0
Answer
– 2
Explanation
Solution
Increasing ̃ f ¢(x) > 0 ̃ 2x + a > 0
̃ a > – 2x in [1, 2]
a > - 2 \end{matrix}$$ as greatest value of – 2x = – 2