Question 761442
2cos^2xtanx = tanx
2cos^2xtanx - tanx = 0
tanx(2cos^2x - 1) = 0
tanx = 0 
   x = 0, pi, 2pi.
2cos^x - 1 = 0
  2cos^2x = 1
   cos^2x = 1/2
    cosx = 1/sqrt2
  x = pi/4, 7pi/4

[0,pi/4,pi,7pi/4 and 2pi]
Hope this helps.
:-)