1.

If the equation `cof^4x-2cos e c^2x+a^2=0`has at least one solution, then the sum of all possible integral valuesof a is equal toa. 4b. 3 c.2 d. 0A. 4B. 3C. 2D. 0

Answer» Correct Answer - D
`cot^4x-2(1+cot^2x)+a^2=0`
`or cot^4x-2cot^2+a^2-2=0`
`or (cot^2x-1)^2=3-a^2`
To have at least one solution, `3-a^2ge0`
`or a^2-3le0`
`a in[-sqrt3,sqrt3]`
Integral values are -1,0,1, therefore, the sum is 0.


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