1.

If the equation in x given by (2(1/(cos^(-1)x)))^(2pi)-(a+1/2)(2(1/(cos^(-1)x)))^pi-a^2=0has only one real solution then exhaustive set of values of 'a' is

Answer»

`(-3,-1)`
`(-oo,-3]U[1,oo)`
`(-oo,-3)U(1,oo)`
`[-3,oo)`

Solution :Let `2^(x/(cos^(-1)x))=t rArr t ge 2 `
EQUATION becomes `t^2-(a+1/2)t-a^2=0`
has ONE roots 2 or greater than 2 and other root LESS than 2, f(2) `le` 0.
`rArr 4-(a+1/2)2-a^2 le 0`
`a^2+2a-3 le 0`
`(a+3)(a-1) le 0`
`a ge -3` or `a le 1`


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