Use trigonometric identities to simplify each expression. a) (1 + cos(x))(1 – cos(x))
b) 1/tan^2(x) – 1/cos^2(x)
c) sec^2(π/2 – x ) [sin2(x) – sin4(x)]

Will mark determine whether the conjecture is true or false. give a counterexample for any false conjecture. given: points r, s, and t conjecture: r, s, and t are coplanar. a) false; the points do not have to be in a straight line. b) true c) false; the points to not have to form right angles. d) false; one point may not be between the other two.