Final answer:
The sin of -315° in fraction form is -1/√2.
Step-by-step explanation:
To find sin(-315°) in fraction form, we need to first determine the reference angle. The reference angle is the positive acute angle between the terminal side of the given angle (-315°) and the x-axis. In this case, the reference angle is 45°. Since sin is negative in the fourth quadrant, we can use the trigonometric identity sin(-θ) = -sin(θ) to find the sin of -315°. Therefore, sin(-315°) = -sin(45°) = -1/√2. So, sin(-315°) in fraction form is -1/√2.