A problem about the limit of higher numbers When x tends to 2, the square of y = x tends to 4|

A problem about the limit of higher numbers When x tends to 2, the square of y = x tends to 4|

[1]
① For ε = 0.001 > 0,
To make: | x ^ 2-4 | < ε = 0.001 hold,
Let: | X-2 | < 1, then: | x + 2 | = | 4 + (X-2) | ≤ 4 + | X-2|