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**nycmathguy****Member**- Registered: 2021-06-02
- Posts: 53

Use either a graph or a table to investigate each limit.

1. limit of sqrt{| x | - x} as x tends to 2 from the left.

2. limit of cuberoot{[ x ] - x}》as x tends to 2 from the left.

Note:

For question 1 in the radicand, we have the absolute value of x minus x.

For question 2 in the radicand, we have the step function [ x ] minus x.

I prefer the table method. What values of x can I use for each function as x tends to 2 from the left side?

*Last edited by nycmathguy (2021-06-10 13:03:03)*

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**Bob****Administrator**- Registered: 2010-06-20
- Posts: 9,207

hi

For question 1, you can start with x = 1.9 There's no need to go near negative values as we want to approach x = 2 and so there's no need for the absolute function at all.

Just treat this as sqrt(x-x)

Q2. More information needed concerning the step function.

If you look here http://www.mathwords.com/f/floor_function.htm

and compare with http://www.mathwords.com/c/ceiling_function.htm

you'll see that two graphs are possible and it makes a difference to the limit.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Sometimes I deliberately make mistakes, just to test you! …………….Bob

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**nycmathguy****Member**- Registered: 2021-06-02
- Posts: 53

Bob wrote:

hi

For question 1, you can start with x = 1.9 There's no need to go near negative values as we want to approach x = 2 and so there's no need for the absolute function at all.

Just treat this as sqrt(x-x)

Q2. More information needed concerning the step function.

If you look here http://www.mathwords.com/f/floor_function.htm

and compare with http://www.mathwords.com/c/ceiling_function.htm

you'll see that two graphs are possible and it makes a difference to the limit.

Bob

I am not too familiar with the step function. I will check out the links.

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