1.

One of the roots of the equation `8x^(3)-6x+1=0` isA. `cos 10^(@)`B. `cos 80^(@)`C. `cos 30^(@)`D. `sin 30^(@)`

Answer» Correct Answer - 2
`4x^(3)-3x=-(1)/(2)`
`implies sin 3theta=sin 30^(@),x=sin theta`
`implies theta =10^(@)`
i.e. `sin 10^(@)` is a root
i.e ` cos 80^(@)` is a root


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