When a function is not defined around the point c (see the notation in the equation above), but only to the left or right of point c, then the limits are called the left-limit and right-limit at c. The formal left- and right-limit equations are the same as the usual limit equation, except below the “lim” sign, the x → c is written as x → c+ for the left-limit and x → c+ for the right limit.