Write the number of sulutions of the equation tan x +sec x = 2 cos x in the interval [0,2π].
tan x+ sec x=2 cos x1+sin x=2 cos2 x2(1−sin2 x)=1+sin x2 sin2 x+sin x−1=0(2 sin x−1)(sin x+1=0)sin x=12 Or−1x=π6,5π6,3π2Thus,there are 3 solutions in interval[0,2π].