Trigonometry problem? help
Favorites|Homepage
Subscriptions | sitemap
HOME > > Trigonometry problem? help

Trigonometry problem? help

[From: ] [author: ] [Date: 12-05-11] [Hit: ]
Take arcsin(1/2) you get 30°, the other angle is 150° because it is above the x-axis and gives a positive trig value.......
I really need help solving this problem, I don't know how to...
Find all values of θ in the interval 0≤θ<360° that satisfy the equation
2sin^2(θ)+sin(θ)=1
Show work:



thank you.. 10 pts (5 stars) best answer

-
Use the quadratic formula or factor to get (2sin(θ) - 1)(sin(θ) + 1)=0

You should obtain sin(θ)= -1 or sin(θ) = 1/2

The sin(θ) is -1 at 270°, The sin(θ) is 1/2 at 30° and 150°. Take arcsin(1/2) you get 30°, the other angle is 150° because it is above the x-axis and gives a positive trig value.

-
Here we go:
2sin^2(θ) + sin(θ) = 1
{sin(θ)}(2sin(θ) + 1) = 1
=>sin(θ) = 1 or 2sin(θ) + 1 = 1
(θ) = sin^-1(1) or 2(θ) = sin^-1(0)
(θ) = 90 degrees or 2(θ) = 0 implies that (θ) = 0 degrees
1
keywords: problem,Trigonometry,help,Trigonometry problem? help
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .