Question

What is the value of the y-coordinate of point A?

Answer 1

Step-by-step explanation:

x/y = cot 15⁰

x = y cot 15⁰ ..... (i)

since, this is unit circle.

hence, x² + y² = 1

from eq. (i)

y² cot² 15⁰ + y² = 1

y² (cot² 15⁰ + 1) = 1

y² cosec² 15⁰ = 1

y² = sin² 15⁰

y = ± (√3 - 1)/2√2

since y lines in II quadrant,

hence, y = - (√3 - 1)/2√2

or

y = (1 - √3)/2√2