domain is how far it travels in the x axis. for this, it would be [0, infinity) usually you’d use an infinity sign, but i can’t find that on my phone. range is same as domain but for y axis. so here it’ll be (-infinity, infinity). you use these [] when you can be on the number. you use there () when you can’t be on the number (or it’s infinity). you use {} when you want to list them.