Sequence and series

Why can't we apply AmGm here?

@kalpita what is the answer

@nizam
Answer is 26

@kalpita
Where am I going wrong?? Pls help


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@kalpita solve it by doing differentiation the answer will be right!! By first differentiation we get x=0, sqrt(3/2) and by second differentiation we get x=0 for minimum and u get the answer

@saumilparsodkar we can't apply AM, GM and be sure that it will definitely be the minimum of the expression. We need to check if the equality condition is fulfilled ie A=B. HERE its. Not possible as we get cos^4x=18/8 which is not possible due to restricted range of cosx

@varsha
you are right.