Q. 79
Mark (√) against the correct answer in the following:
is increasing in
A. (-1, 1)
B. (-1, ∞)
C. 
D. none of these
Answer :
⇒ For critical points f’(x) = 0
When f’(x) = 0
We get x = 1 or x = -1
When we plot them on number line as f’(x) is multiplied by –ve sign we get
For x>1 function is decreasing
For x<-1 function is decreasing
But between -1 to 1 function is increasing.
∴ Function is increasing in(-1,1).
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