Question #7ec3c
2 Answers
Feb 13, 2018
Explanation:
Using identity
We get:
1 + cos t - 3cos t = 0
Trig Table and unit circle give 2 solutions:
Feb 13, 2018
Give a look here...
Reference proof:-
cosθ=cos2(θ2)−sin2(θ2)
⇒cosθ=cos2(θ2)−1+cos2(θ2)
⇒cosθ=2cos2(θ2)−1
Explanation:
2cos2(θ2)−3cosθ=0
⇒(cosθ+1)−3cosθ=0
⇒2cosθ=1
⇒cosθ=12
⇒cosθ=cos(π3)
⇒θ=2nπ±(π3) [n∈I] for
n=0→θ=π3
forn=1→θ=5π3 Hope it helps...
Thnx...