if cosØ=0.6 and 0°<Ø<90°, find the exact value of 2Ø

Answer 1

remember cos^2 Ø + sin^2 Ø = 1
.36 + sin^2 Ø = 1
sin^2 Ø = .64
sinØ = .8

sin 2Ø = 2sinØcosØ
= 2(.8)(.6)
= .96

2Ø = sin^-1 (.96) or arcsin(.96)