Asked by Anonymous
cotθ=3, cos<0. Find the exact value of sin θ/2 using half-angle formula. Please help!
Answers
Answered by
Steve
if cot > 0 and cos < 0, then you are in QIII
cotθ = 3
cosθ = -3/√10
sin θ/2 = √((1-cosθ)/2)
= √((1+3/√10)/2)
Note that since θ is in QIII, θ/2 is in QII, and so sinθ is positive.
cotθ = 3
cosθ = -3/√10
sin θ/2 = √((1-cosθ)/2)
= √((1+3/√10)/2)
Note that since θ is in QIII, θ/2 is in QII, and so sinθ is positive.
Answered by
Anonymous
WOW!! Thanks so much! Looks like I knew how to solve it the whole time, just needed to see the proof I guess