Question Number 103921 by Rio Michael last updated on 18/Jul/20

Prove that ∀ x ∈ R^�  , ∣ cos x ∣ ≤ 1 − sin^2  x

Answered by Worm_Tail last updated on 18/Jul/20

cosx=(√(1−sin^2 x        ))      ∣cosx∣= (√(1−sin^2 x))    ≤1−sin^2 x                   ∣cosx≤1−sin^2 x

Commented byRio Michael last updated on 18/Jul/20

perfect sir thanks