Question

explain how you will find the coordinate of P(14pi/3) if you knew the coordinate of P(pi/3)

Answer 1

I will try to guess what you mean ....

If π/3 is a rotation angle on a unit circle (60°)
then 14π/3 = 4 + 2π/3 or 4 rotations + 2π/3
this would put you into quadrant II (120°)

a point with angle π/3 and a point with angle 2π/3 has the same y coordinate

so the y - coordinate for P(π/3, .....) and P(14π/3, ....) would be the same.

Let me know if this is what you were asking.