The denominator of the numerator is divided by x at the same time, and the x to be divided in the denominator becomes √ x 2 under the root sign, that is, all parts under the root sign are divided by the square of x, and finally the above result is obtained.

In addition, it should be noted that because this problem X tends to be positive infinity, it is greater than 0; If x tends to negative infinity, then x =-√ x 2, which is more negative than that.