Answer:
(2/5)√5 ≈ 0.894427
Step-by-step explanation:
You require the y-coordinate of the point that satisfies two equations:
x^2 +y^2 = 1
y = 2x
Substituting for x, we have ...
(y/2)^2 +y^2 = 1
y^2(5/4) = 1
y^2 = 4/5
y = (2/5)√5 ≈ 0.894427
The sine of the angle is (2/5)√5 ≈ 0.894427.
