fx=Sce−11+Cos2x where. is g.i.f. Then range of fx=
π4,π3
0,π2
π4,π2
0,π3
We know that 0≤cos2x≤1.
⇒1≤1+cos2x≤2
So 1+cos2x= either 1 or 2
⇒Sec−11+cos2x=Sec-11 or Sec-12 =0 orπ3 ∴range of fx=0,π3