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Application Of Derivatives

Question
CBSEENMA12035293

Prove that the function x2 – x + 1 is neither increasing nor decreasing on (0, 1).

Solution

Let straight f left parenthesis straight x right parenthesis space equals space straight x squared minus straight x plus 1
      straight f apostrophe left parenthesis straight x right parenthesis space equals space 2 straight x minus 1
Now,    straight f apostrophe left parenthesis straight x right parenthesis space greater than space 0 space space space space for space space straight x greater than 1 half space space and space straight f apostrophe left parenthesis straight x right parenthesis space less than 0 space space for space straight x space less than space 1 half.
therefore space space space straight f left parenthesis straight x right parenthesis space is space increasing space in space open parentheses 1 half comma space 1 close parentheses space and space decreasing space in space open parentheses 0 comma space 1 half close parentheses
therefore space space space space straight f left parenthesis straight x right parenthesis space is space neither space increasing space nor space decreasing space in space left parenthesis 0 comma space 1 right parenthesis