tanxsinx + cosx = secx , ,(sin^2x)/cosx + cosx/cosx = 1/cosx, ,sin^2x + cosx = 1 , ,(1 - cos2x)/2 + cosx = 1 , ,1 - cos2x + 2cosx = 2 , ,1 - (2cos^2x - 1) + 2cosx = 2, ,2cos^2x + 2cosx -2 =0, ,(2cosx - 1)^2 = 0, ,cosx = 0.5, ,basic angle = 60, ,x = 60, 300 degrees