Posted by **Kay** on Wednesday, October 24, 2007 at 11:00am.

Solve the following interval

0<_ (less than or equal to)0(Theta)<2pi:

1. sin0(theta) + sin2 0(theta) = 0

2. 2cos^20 (theta) + cos0 (theta) -1 = 0

- Trig -
**Reiny**, Wednesday, October 24, 2007 at 3:43pm
sinӨ + sin2Ө = 0

recall that sin2Ө = 2sinӨcosӨ

so sinӨ + sin2Ө = 0

sinӨ + 2sinӨcosӨ = 0

sinӨ(1+2cosӨ)=0

sinӨ = 0 or 2cosӨ = -1

sinӨ = 0 or or cosӨ = -1/2

Ө = 0,pi,2pi or Ө=2pi/3,4pi/3

in degrees: 0,180,360,120,240

## Answer this Question

## Related Questions

- help help helpppp--math - 1)Use the definitions sin0(theta) = y/r, cos0(theta...
- Math - 1)Use the definitions sin0(theta) = y/r, cos0(theta) = x/r and/or tan0(...
- Trigonometry - Thank you STEVE!!!!! Suppose that Cos (theta) = 1/square root 2 ...
- Mathamatics - Solve the following trigonometry identities. a) 1-cos2(theta) = ...
- trig - If sin theta is equal to 5/13 and theta is an angle in quadrant II find ...
- Math Trig Please Help!!! - Find exact values for all the solutions to the ...
- math - knowing that 2(theta) can be written as theta + theta, find the ...
- calculus - Find circumference of the circle r=2acos theta. s= Int (0 to 2pi) of ...
- Precalc with Trig - What value(s) of theta (0 less than or equal to theta less ...
- trig - If cosecant of theta equals 3 and cosine of theta is less than zero, find...

More Related Questions