Tuesday

January 27, 2015

January 27, 2015

Posted by **Anonymous** on Sunday, November 22, 2009 at 1:11pm.

x is all real numbers , [0, 2 pi]

using a trigonometric identify

2cos^2x + sinx - 1 = 0

- Advanced Functions -
**Reiny**, Sunday, November 22, 2009 at 4:33pm2cos^2x + sinx - 1 = 0

2(1 - sin^2x) + sinx - 1 = 0

2 - 2sin^2x + sinx - 1 = -

2sin^2x - sinx -1 = 0

(2sinx + 1)(sinx - 1) = 0

sinx = -1/2 or sinx = 1

from sinx = -1/2, x = pi + pi/6 or 2pi - pi/6

x = 7pi/6 radians or 11pi/6 radians ,

(210º or 330º)

from sinx = 1, x = pi/4 radians, (90º)

**Answer this Question**

**Related Questions**

Advanced Functions - Determine the solutions for: (cos x)/(1 + sinx) + (1 + sinx...

advanced functions - Determine approximate solutions for this equation in the ...

math - the problem is 2cos^2x + sinx-1=0 the directions are to "use an identity ...

Trigonometry - Find all solutions on the interval (0,2pi): 2-2cos^2=sinx+1

Precalculus - Please help!!!!!!!!!!! Find all solutions to the equation in the ...

Math - cos x = -0.6 , 0 <= theta <= 2pi Use inverse trigonometric ...

math - describe the solutions of 4<or=n+2 mult. choice a all real numbers ...

Algebra - The vertex of a parabola is at (-2,4), and the x-intercepts are at -6 ...

Maths - crazy maths question which involves graphi - This is a question that ...

math 2 - let f and g be two functions defined by: f(x)=x+5, with domain all real...