4. simplify the expression. (6 points) sine of x to the second power minus one divided by cosine of negative x a) -sin x b) cos x c) sin x d) -cos x 5. find all solutions in the interval [0, 2π). (6 points) sin2x + sin x = 0 a) x = 0, π, four pi divided by three , five pi divided by three b) x = 0, π, pi divided by three , two pi divided by three c) x = 0, π, pi divided by three , five pi divided by three d) x = 0, π, three pi divided by two