If cos (ϕ)= 0.7087 and 3π/2≤ ϕ ≤2π, approximate the following to four decimal places. (a) sin(ϕ)= ( ) (Round to four decimal places.) (b) tan(ϕ)=( ) (Round to four decimal places.)

Question

If cos (ϕ)= 0.7087 and 3π/2≤ ϕ ≤2π, approximate the following to four decimal places.

(a) sin(ϕ)= ( ) (Round to four decimal places.)

(b) tan(ϕ)=( ) (Round to four decimal places.) 

Answer 1

sin(Φ) = - √(1 - 0.7087²) = - 0.7055;

tan(Φ) = sin(Φ)/cos(Φ) = - 0.7055/0.7087 = - 0.9955