http://gyazo.com/97dbcc6c159b083ec68c157711474f71 Number 11
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|f(x) - 6| < 3 implies: -3 < f(x) - 6 < 3 add 6 throughout 3 < f(x) < 9 Read the graph to see when f(x) = 3 and f(x) = 9. f(1) = 3 and f(5) = 9 f(1) < f(x) < f(5) Therefore, the maximum delta can be is 5 - 3 = 2. (or 3 - 1 = 2)
Oo ok :)
Follow the same procedure for part 2.
It saying the answer for b is 1/2 ?
correct. Do you need the steps?
Yes so I can see it out
Please :)
@aum
@e.mccormick
It is simply following the same steps but starting with < 1 rather than < 3.
Ok so if i do that I get -1<f(x)-6<1 Then I get 5<f(x)<7 But don't get 1/2 as the answer
Did you look at the f(x) for those values?
F(2 1/2) = 5
And f(3 1/2) = 7 id what I get
Yes. We are taking the limit as x approaches 3. So the maximum we can go from 3 is: +1/2 or -1/2 So maximum |delta| = 1/2
Oooo. Ok :)
Yah, you are looking at how far the input values are from the center value. So because you are looking at \(x\rightarrow 3\) you need to look at how far each of those are from 3. That is where the \(\pm \dfrac{1}{2}\) comes in.
3 + 1/2 = 3.5 3 - 1/2 = 2.5 And those are the domain values you found for that epsilon range.
Thanks for both for the help
You are welcome.
I tried to map your function to help with the meaning of \(\epsilon - \delta\), but did not quite get it. https://www.desmos.com/calculator/qbqhmrz3mb What this whole thing is about is the input, \( \delta\), and it's relationship to the output, \( \epsilon\), when you are looking for something that is "close enough." Lets say you don't know the answer and can't easily calculate it. But, you want to get within \( \epsilon\) of the correct answer. With this process you can find the \( \delta\) that will get you there. Now, not all functions are nice and ballanced so the \(\pm\) will be the same on both sides. In those cases, take the smaller \( \delta\) distance. The reason why is because the larger would be incorect for one of the answers, but the smaller is correct for both.
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