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Find the intervals in which the following functions are strictly increasing or decreasing:
Applications of Derivatives | CBSE | Class 12 | Exercise 6.2 | Maths | NCERT
Find the intervals in which the following functions are strictly increasing or decreasing:

(a)    

(b)    

SOLUTION:

(a) Given: 

     ……….(i)

Now 

 

Therefore, we have two sub-intervals  and 

For interval  taking  (say), from eq. (i),  < 0

Therefore,  is strictly decreasing.

For interval  taking  (say), from eq. (i),  > 0

Therefore,  is strictly increasing.

(b) Given: 

  =   ……….(i)

Now 

 

Therefore, we have two sub-intervals  and 

For interval  taking  (say), from eq. (i),

 > 0

Therefore,  is strictly increasing.

For interval  taking  (say), from eq. (i),

 < 0

Therefore,  is strictly decreasing.

 

i

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