If cos−1n2π>2π3 then the minimum and the maxi mum values of integer n are respectively
– 6 and – 4
4 and 6
– 6 and – 3
none of these
We have,
2π3<cos−1n2π<π⇒cos2π3>n2π>cosπ⇒−1<n2π<−12⇒−2π<n<−π⇒−6<n<−4