Find the intervals in which the following functions are strictly increasing or decreasing:
10 – 6x – 2x2
It is given that function f(x) = 10 – 6x – 2x2
f’(x) = -6 – 4x
If f’(x) = 0, then we get,
⇒ x =
So, the point x = divides the real line into two disjoint intervals,
So, in interval
f’(x) = -6 – 4x < 0
Therefore, the given function (f) is strictly decreasing in interval.
And in interval
f’(x) = -6 – 4x > 0
Therefore, the given function (f) is strictly increasing in interval.
Thus, f is strictly decreasing for x> .