1. cosx+1=0; x ∈ R 2. 4sin^2 x - 1 = 0; x ∈ R 3. 2cos^2 x + 3cosx + 1 =0;0 ≤ x < 2π
cosx = -1 4sin^2x-1 = 0 sinx = ±1/2 2cos^2x+3cosx+1 = 0 (2cosx+1)(cosx+1) = 0 cosx = -1/2 or -1 Now find angles in the proper quadrants for those solutions. And don't forget your Algebra I now that you're doing trig!
You can ask a new question or answer this question.