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What is sin(2θ)sinθ=cosθ using the interval 0 ≤ θ < 2 π?
θ=π/2 and 3π/2
θ=π/4 and 3π/4 (in quadrants I and II where sin>0)
and 5π/4 and 7π/4 (in quadrants II and IV where sin<0)
θ=π/2, 3π/2, π/4, 3π/4, 5π/4 and 7π/4