@stdlib/math-base-special-hacoversin (npm): Compute the half-value coversed sine.
Keywords: stdlib|stdmath|mathematics|math|hacoversin|hacoversine|versed sine|half-value|coversed|sinus versus|hacoversinus|hcv|hacov|semicoversin|cohaversine|versed|sine|sin|trig|trigonometry|radians|angle|javascript|node|node-js|nodejs|sinus-versus|versed-sine