Limits involving absolute value.

In summary, the first limit is equal to 0 because the value of sin|x| approaches 0 as x approaches infinity. For the second limit, since the function is continuous at x=0, we can simply substitute x=0 and get a value of 2. However, if we want to show that the function is continuous, we can also use one-sided limits to prove it.
  • #1
singedang2
26
0
[tex]\lim_{x\rightarrow\infty}\frac{\sin|x|}{x}[/tex]

[tex]\lim_{x\rightarrow 0}\frac{|x|-|x-2|}{x-1}[/tex]

thanks!
 
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  • #2
ok hello people this is my first post! woot! okily i gtg to da shops now, so basically i just answer ur post bout da limits...ok well the first one, sin lxl divided by x, approaching infinity, well you see, think about it this way, sin lxl has to be between -1, and 1, as we know. now, 1/infinty= 0
-1/infinity=-0=0, anything inbetween will also equal zero, except zero it self, but as u can see, the limit as it approaches that is also zero, i know I am not very clear..ok basically its zero..and the 2nd one, a little easier :D well basically people use limits to find out wat the value something wud approach at an asymtote or a discontinous point. however, in this case, there is no discontinuity at point zero, so you can just sub it straight in and you'll be fine. so its (0 - l0-2l)/(0-1)= (0- +2)/-1= 2

i know my layout is bad, i hope u get da gist of it..
 
  • #3
For the first, since x is approaching infinity, x is always positive and |x|= x.

For the second, do the two onesided limits: For x close to 0 and x> 0, |x|= x and |x- 2|= 2- x ( x is close to 0 so x< 2, x- 2 is negative). For x close to 0 and x< 0, |x|= -x and |x-2|= 2- x (x is still less than 2).

(Gib Z is correct- since the second function is continuous at x= 0, you can just substitute x= 0 but it might be that you want to find the limit in order to show that the function is continuous.)
 

1. What is the definition of absolute value?

The absolute value of a number is the distance of that number from zero on a number line. It is always a positive value.

2. How does absolute value affect limits?

Absolute value can impact the behavior of limits, as it removes the negative sign from a number. This means that when taking the limit of a function involving absolute value, we must consider both the positive and negative values of the input.

3. What is the limit of a function involving absolute value at a specific point?

The limit at a specific point for a function involving absolute value may not exist, as the function may approach different values from the left and right sides of the point. In this case, the limit would be undefined.

4. How do you solve limits involving absolute value algebraically?

To solve a limit involving absolute value algebraically, we can split the function into two separate pieces, one for the positive values and one for the negative values. Then, we can take the limit of each piece separately and combine the results to find the overall limit.

5. Can limits involving absolute value be graphically represented?

Yes, limits involving absolute value can be graphically represented. The graph may have a "corner" or "pointed" shape at the point where the absolute value function switches from positive to negative or vice versa. This can help us visualize the different behaviors of the function from the left and right sides of the point.

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