(x*255/127-1)*step(127/255-x)+step(x-128/255)*(x*255/127-128/127) from x = 0.45 to 0.55

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.