Question

The interval in which y=x²e^-x is increasing is

(A)  (∞,∞)      

(B) (-2,0)

(C) (2,∞  )

(D) (0,2)

Answer 1

We have,

y=X²e^-x

The points x = 0 and x = 2 divide the real line into three disjoint intervals

∴ f is strictly increasing on (0, 2).
Hence, f is strictly increasing in interval (0, 2).
The correct answer is D.