Posted by **Cynthia** on Friday, August 3, 2012 at 3:17pm.

Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to

two decimal places.

Please explain.

- Trigonometry -
**Steve**, Friday, August 3, 2012 at 3:42pm
cos2x (1 - 3sinx) = 0

cos2x = 0 or sinx = 1/3

cos 2x = 0:

2x = k*pi/2 where k is an integer

x = pi/4, 3pi/4, 5pi/4, 7pi/4

sinx = 1/3:

x = 0.34 or pi-0.34

## Answer This Question

## Related Questions

- trigonometry - 5. Find the complete exact solution of sin x = -√3/2. 9. ...
- trigonometry - 5.Find the complete exact solution of sin x = -√3/2. 10. ...
- Trigonometry desperate help, clueless girl here - 2. solve cos 2x-3sin x cos 2x...
- trig help much appreciated! :)) - 1. Find the complete exact solution of sin x...
- Trigonometry - 1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two ...
- Trigonometry - Solve tan2 x + tan x – 1 = 0 for the principal value(s) to two ...
- Math, derivatives - Let g(x) = sin (cos x^3) Find g ' (x): The choices are a) -...
- Trigonometry - Write equivalent equations in the form of inverse functions for a...
- Trigonometry - Please review and tell me if i did something wrong. Find the ...
- Trigonometry - I have some trigonometric equations to do, but I'm pretty lost, ...

More Related Questions