Applications Of Derivatives Question 5
Question: Let $ y=x^{2}{e^{-x}} $ , then the interval in which y increases with respect to x is
[MNR 1994; Kurukshetra CEE 1998]
Options:
A) $ (-\infty ,\infty ) $
B) $ (-2,,0) $
C) $ (2,\infty ) $
D) $ (0,,2) $
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Answer:
Correct Answer: D
Solution:
$ \frac{dy}{dx}=\frac{-1}{e^{x}}x(x-2) $ is $ +ve $ when $ x(x-2) $ is $ -ve $ i.e., x lies in the interval (0, 2), exponential function as we know is always $ +ve $ .
BETA
