1.

If `|cos^(-1)((1-x^2)/(1+x^2))|

Answer» `|cos^-1((1-x^2)/(1+x^2))| lt pi/3`
`=> - pi/3 lt cos^-1((1-x^2)/(1+x^2)) lt pi/3`
we know, range of `cos^-1y` is from `0` to `pi`.
`:. 0 le cos^-1((1-x^2)/(1+x^2)) lt pi/3`
`=> 1/2 lt (1-x^2)/(1+x^2) le 1`
`=> 1+x^2 lt 2-2x^2 le 2+2x^2`
`=> 0 le x^2 lt 1/3`
`=> :. x in (-1/sqrt3,1/sqrt3).`
So, option `c` is the correct option.


Discussion

No Comment Found