Posted by Maurice on Thursday, March 22, 2012 at 11:26am.
7)
since cos 2x = 2cos^2 x - 1, we have
6cos^2 x - 5cos x - 4 = 0
(2cos x + 1)(3cos x - 4) = 0
cos x = -1/2 --> x = 2pi/3 or 5pi/3
cos x = 4/3 --> no solution
8)
(sin x - 2)(2sin x - 1) = 0
sin x = 2 --> no solution
sin x = 1/2 --> x = pi/6 or 5pi/6
9)
3sec^2 x = 4
sec x = ±2/√3
or, more familiarly,
cos x = ±√3/2
x = pi/6, 5pi/6, 7pi/6, 11pi/6
10)
tan X = 0 --> x = 0, pi
tan x = 1 --> x = pi/4, 5pi/4
Related Questions
Math - Solving for Trig Equations - Solve the following equation for 0 less than...
Pre-calculus - solve 4 sin^2x + 4 sqrt 2 cos x-6=0 for all real values of x. ...
Math - Solving Trig Equations - Solve each equation for o is less than and/or ...
Math - Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin...
Precalculus - Solve Cos^2(x)+cos(x)=cos(2x). Give exact answers within the ...
Math - Solving Trig Equations - What am I doing wrong? Equation: sin2x = 2cos2x ...
math - Prove that for all real values of a, b, t (theta): (a * cos t + b * sin t...
TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...
trig - 2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3...
Trigonometry - I have some trigonometric equations to do, but I'm pretty ...
For Further Reading
