Find the principal values of `sec^(-1)(2/(sqrt(3)))` and `sec^(-1)(-2)`

Explanation

`sec^(-1)((sqrt(3))/2)`

`secx=frac{2}{sqrt3}`

`sec theta=frac{1}{cos theta}`

`x=pi/6`

`sec^(-1)((sqrt(3))/2)=pi/6`


`sec^(-1)(-2)`

`sec theta=-sec(pi/3)`
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