Change of magic number to 2 * math.pi

lib/wibox/container/scroll.lua

@@ -569,7 +569,7 @@ function scroll.step_functions.smooth_back_and_forth(elapsed, size, visible_size
     local state = ((elapsed * speed) % (size)) / size
     -- The cosine function is scaled to map [0,1] to [0,2π] then it’s output is
     -- scaled from [1 -- -1 -- 1]  to [0 -- 1 -- 0]
-    return (size - visible_size) * (0.5 - 0.5*math.cos(state*6.2832))
+    return (size - visible_size) * (0.5 - 0.5*math.cos(state * 2 * math.pi))
 end
 
 return scroll