Find all x that satisfy the given equations for 0 less than
Solution
For all equations solution for:0<=x <=2pi
6. (cos^2x -4)/(cosx -2) =1
cos^2x -4 = cosx -2
cos^2x - cosx -4 +2 =0
solve the quadratic equation:
cos^2x -2cosx +cosx -2 =0
cosx( cosx -2) + 1( cosx -2) =0
(cosx +1)(cosx -2) =0
cosx =2 .Neglect the solution
cosx =-1
x = pi is the solution
10 ) sqrt3 secx*cscx = 2cscx
sqrt3 secx*cscx - 2cscx =0
cscx( sqrt3secx -2) =0
cscx =0 --->No solutions
sqrt3secx =2 ----> sqrt3/cosx =2
cosx = sqrt3/2 ---> x= cos^-1(sqrt3/2)
x = pi/6 , 2pi-pi/6 = pi/6 , 11pi/6 are the solutions
11. 4tan^2x -1 = tan^2x
3tan^2x -1 =0\'
(sqrt3 tanx +1)(sqrt3 tanx -1) =0
tanx = -1/sqrt3 ---> x =pi -pi/6 , 2pi-pi/6 = 5pi/6 , 11pi/6 ( tan is -ve in IInd and IVrth quadrant)
tanx = 1/sqrt3 ----> x = pi/6 , pi+pi/6 = pi/6 , 7pi/6 ( tan is +ve in Ist and IIIrd quadrant)
x =pi/6, 5pi/6 , 7pi/6, 11pi/6 are the solutions

