Posted by **Daisy** on Tuesday, December 4, 2012 at 5:11pm.

Find all real solution of the equation sin^2x = -2+2cosx

- Math -
**Steve**, Tuesday, December 4, 2012 at 6:50pm
since sin^2 = 1-cos^2,

1-cos^2 = -2 + 2cos

cos^2 + 2cos - 3 = 0

(cos+3)(cos-1) = 0

cos=1, so x = 0,2pi,4pi,...

why not -3?

## Answer This Question

## Related Questions

- math - Solve 2cosx-sin^x +2 =0 for all real values of x
- Math - Find all real solutions of the equation. (Enter your answers as a comma-...
- math - tanx+secx=2cosx (sinx/cosx)+ (1/cosx)=2cosx (sinx+1)/cosx =2cosx ...
- college algebra - Find all real solutions of the equation. (Enter your answers ...
- Math - Solving for Trig Equations - For the following equation, why cannot I not...
- Math - The twice–differentiable function f is defined for all real numbers and ...
- Math, please help - Which of the following are trigonometric identities? (Can be...
- math - Ok, so when you are solving an equation, and you have an answer such as ...
- precal - Find all solutions of the equation in the interval , 02π . =2sin2x...
- math - Prove that for all real values of a, b, t (theta): (a * cos t + b * sin t...

More Related Questions