Trigonometry proble...
 
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Trigonometry problem

 
Prasoon Parihar
(@parihar)
Eminent Member

The number of the real roots of the equation 2cos(x(x + 1)) = 2x + 2-x is

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Topic starter Posted : 28/10/2020 3:43 pm
Rahul Singh
(@rahul)
Admin

As we know maximum value of cos A = 1 at A =0
So maximum value of 2cos (x ( x + 1 ) ) = 2*1 =2
Minimum value of 2^x + 2^(-x) = 2 ( as the minimum value of k + 1/k = 2 at k = 1) at x = 0
Thus there is only one possible case when 2cos (x ( x + 1 ) ) = 2^x + 2^-x at x =0
So no of real solution =1

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Posted : 28/10/2020 3:49 pm
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