Application of Derivatives
NCERT Class 12
CBSE
Grade 12
Question:
The interval in which $f(x) = 2x^3 - 3x^2 - 36x + 7$ is strictly decreasing is:
(a) $(-2, 3)$
(b) $(3, \infty)$
(c) $(-\infty, -2)$
(d) $(-3, 2)$
Step-by-Step Solution
$f'(x) = 6(x-3)(x+2) < 0 \Rightarrow x \in (-2, 3)$. [1.0 Mark]
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🎯 Official CBSE Marking Scheme:
Selecting $(-2, 3)$: 1.0 Mark
Correct Answer: $(-2, 3)$
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