Sin(-390) = Sin(390)

Since a full circle is 360 degrees, we can calculate the equivalent angle within a full circle by subtracting 360 from the given angle:

390 - 360 = 30

So, Sin(390) is equal to Sin(30) because the sine function is periodic with a period of 360 degrees.

Sin(30) = 0.5

Therefore, Sin(-390) = Sin(390) = 0.5.