It is known that a (2,0), B (0,2), C (COS θ, sin θ), O are the coordinate origin (1) Vector ac * vector BC = - 1 / 3, find the value of sin2 θ; (2) If ㄧ vector OA + vector OC ㄧ = root 7, and θ∈ (- π, 0), find the angle between vector OB and vector OC | Math enthusiast | Mathematical art

It is known that a (2,0), B (0,2), C (COS θ, sin θ), O are the coordinate origin (1) Vector ac * vector BC = - 1 / 3, find the value of sin2 θ; (2) If ㄧ vector OA + vector OC ㄧ = root 7, and θ∈ (- π, 0), find the angle between vector OB and vector OC

According to the title: vector OA = (2,0), OB = (0,2), and OC = (COS θ, sin θ) 124; vector OA + vector OC 124| (2,0), OB = (0,2), and OC = (2,2,0), OB = (0,2), OC = (2,2), OC = (0,2), OC = (COS θ, and OC (0,2), OC = (0,2,2), OC = (2,2,2,2,2), OC = (2,0,2,0,2,0) vector OA ||\124;\\|\\\\\124;\\\|\\\\|o

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