Given that cos theta = 1/sqrt2, determine possible coordinates.?

For cosθ > 0 and -180° ≤ θ ≤ 0°,
θ is in the fourth quadrant, i.e. sinθ < 0

sin²θ + cos²θ = 1
sin²θ + (1/√2)² = 1
sin²θ = 1/√2
Hence, sinθ = -1/√2  for sinθ < 0

Refer to the diagram below:
The coordinates of P
= P(|OP|cosθ, |OP|sinθ)
= P(|OP|/√2, -|OP|/√2)

If P is (x, y), then either:
1. x = y, with x and y both positive
2. x = -y, with x positive and y negative

Sorry dude, if you're anon you're not going to receive answers.