If, for 0<x< /2, y= [ ( ^2x+ ^4x+ ^6x+ ) _e2 ] is a zero of the quadratic equation x^2-9x+8=0, then the value of x+ x x- x , is

JEE Main Mathematics question

If, for , is a zero of the quadratic equation , then the value of , is

Answer: (B)

The series is a GP with ratio , so its sum is and . The roots of are and ; would need ,

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Question ID VK-021884