If −𝜋 ≤ 𝑥 ≤ 0, then cos−1(cos 𝑥) is:
A)𝑥 B)𝜋−𝑥 C)2𝜋+𝑥 D)2𝜋−𝑥 E)None
arccos cos(-π/4) = π/4
arccos cos(-3π/4) = 3π/4
since -x is not one of the choices, add 2π
so I pick D
That flips QIII,QIV into QII,QI, the principal values of arccos(x)
A)𝑥 B)𝜋−𝑥 C)2𝜋+𝑥 D)2𝜋−𝑥 E)None
arccos cos(-3π/4) = 3π/4
since -x is not one of the choices, add 2π
so I pick D
That flips QIII,QIV into QII,QI, the principal values of arccos(x)