Q. 74
Mark (√) against the correct answer in the following:
is increasing in
A. (-2, 0)
B. (0, 2)
C. (2, ∞)
D. (-∞, ∞)
Answer :
Given f(x) = x2.e-x
⇒ f’(x) = 2x. e-x – x2 e-x
⇒ Put f’(x) = 0
⇒ - (x2– 2x)e-x = 0
⇒ x = 0 or x =2.
Now as there is a -ve sign before f’(x)
When x>2 the function is decreasing
x<0 function is decreasing
But in the interval (0,2) the function is increasing.
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