Answer:
x = - √2/2
Step-by-step explanation:
We know that x = rcosθ and y = rsinθ. The unit circle always have radius of 1 unit. Therefore, r = 1 as defined. Hence:
x = cosθ, y = sinθ
x = cosθ, θ = arcsin(y)
x = cos{arcsin(-√2/2)}
Find the measurement or θ that makes sinθ = -√2/2 and that is π + π/4 = 5π/4.
x = cos(5π/4)
And cos(5π/4) = - √2/2 as well. Hence, x = - √2/2.
