If f(x)=cos2x+sec2x, then
f(x) <1
f(x) = 1
1 < f(x) < 2
f(x) 2
Since, (x−1x)2≥0, ∀ x ϵ R,we have x2+1x2≥2 andHence, f(x)=cos2 x+1cos2 x≥ 2