High number: why 0 < X-Y in the limit of function when independent variable tends to finite value|

High number: why 0 < X-Y in the limit of function when independent variable tends to finite value|

When you learn the definition of "continuity", you will know the difference between the two. Continuity requires that the limit value be equal to the function value, which is equivalent to the formula you wrote to remove the value greater than zero