What is the position vector r⃗ (t) as a function of angle θ(t). for later remember that θ(t) is itself a function of time.?

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What is the x coordinate of the particle?
 x = Rcos(θ(t))

What is the y coordinate of the particle?
 y = Rsin(θ(t))

Correct answer is r⃗  (t) = Rcos(θ(t))i + Rsin(θ(t))i^j^