Ex 6.5,4 - Chapter 6 Class 12 Application of Derivatives

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Ex 6.5,4 Prove that the following functions do not have maxima or minima: (i) ( ) = Given ( ) = Finding maxima or minima ( ) = Putting f (x) = 0 = 0 This is not possible for any value of x. f (x) does not have a maxima or minima. Ex 6.5,4 Prove that the following functions do not have maxima or minima: (ii) g(x) = log x Given g (x) = log x Finding maxima or minima g (x) = 1 Putting g (x) = 0 1 =0 = 1 0 = This is not defined for x. So, g (x) does not have a maxima or minima. Ex 6.5,4 Prove that the following functions do not have maxima or minima: (iii) = 3 + 2 + +1 Given h (x) = x3 + x2 + x + 1 Finding maxima or minima = 3 2 +2 +1 Putting = 0 3 2 +2 +1=0 Here = 3, b = 2, & c = 1 x = 2 4 4(3)(1) 6 x = 2 4 12 6 x = 2 8 6 x = 2 2 2 6 x = Since root has minus sign, x has no real value h (x) does not have a maxima of minima