Recent content by songoku

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    Limit of piecewise function using epsilon delta

    I am very sorry for late reply Thank you very much for all the help and explanation pasmith, PeroK, FactChecker, BvU, Gavran, anuttarasammyak
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    Limit of piecewise function using epsilon delta

    Is calculating the bounds based on one - sided limit like post #24? But in post#15, the delta you take is ##|\sqrt[3]{8+\epsilon}-2|##, not the negative one? By minimum, do you mean ##\delta=\text{min}~(1, \frac{\epsilon}{4})##? Thanks
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    Limit of piecewise function using epsilon delta

    Ah my bad Oh ok, but how about something like this? That example is from textbook and there is part 2 of the working (to show that this ##\delta## works). Is this part not needed and I can just stop at part 1 after stating ##\delta=\frac{\epsilon}{4}##? I am sorry I don't get this. In post...
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    Limit of piecewise function using epsilon delta

    I am trying to but sorry I don't have idea how to continue without choosing a certain value for ##\delta##. What I practice up until now is the one which always choose the value of ##\delta##. If not choosing any value for ##\delta##, what is the continuation after ##\delta=\text{min}...
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    Limit of piecewise function using epsilon delta

    Then how to continue the proof? Let: ##\delta_1=\text{min}\{\sqrt[3] {8-\epsilon}-2, \sqrt[3] {8+\epsilon}-2\}## ##\delta_2=\text{min}\{\sqrt{4-\epsilon}-2, \sqrt {4+\epsilon}-2\}## ##\delta=\text{min} \{\delta_1, \delta_2 \}## For left limit: ##2-\delta<x<2##. How to change this into ##|x^3...
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    Limit of piecewise function using epsilon delta

    Wait, I don't need to choose which one is the minimum? But then when I want to prove it, what should I put as ##delta##? Oh I have to take one common ##\delta## and use it for left and right side limit? Thanks
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    Limit of piecewise function using epsilon delta

    For left side limit ##(x\to 2^{-})##, the ##\delta=|\sqrt[3] {8+\epsilon}-2|## For right side limit, ##(x\to 2^{+})##, the ##\delta=|\sqrt{4+\epsilon}-2|## Is this what you mean? Yeah I am having difficulty getting the ##|x-2|## to complete the proof. I am trying to use ##a-\delta<x<a## for...
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    Limit of piecewise function using epsilon delta

    How to continue the working to complete the proof? For left side limit, let ##\delta=|\sqrt[3] {8+\epsilon}-2|##. Taking ##\delta>0## and ##0<\epsilon<8## , then ##\delta=|\sqrt[3] {8+\epsilon}-2|=\sqrt[3] {8+\epsilon}-2## So: $$2-(\sqrt[3] {8+\epsilon}-2)<x<2$$ $$4-\sqrt[3] {8+\epsilon}<x<2$$...
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    Limit of piecewise function using epsilon delta

    Sorry I don't understand. Isn't ##f## defined in the question? For ##x\to 2^{-}, f(x) = x^3 +2## and for ##x\to 2^{+}, f(x)=x^2 + 6##. Is this what you mean? Ok so the the right side limit, I also assume ##0<\epsilon<4## so the minimum would be ##|\sqrt{4+\epsilon}-2|## Is it ok to have two...
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    Limit of piecewise function using epsilon delta

    1) proofing ##\lim_{x \to 2^{-} f(x)=10}## $$|x^3 +2-10|<\epsilon$$ $$-\epsilon<x^3-8<\epsilon$$ $$8-\epsilon<x^3<8+\epsilon$$ $$\sqrt[3] {8-\epsilon}<x<\sqrt[3] {8+\epsilon}$$ $$\sqrt[3] {8-\epsilon}-2<x-2<\sqrt[3] {8+\epsilon}-2$$ $$|\sqrt[3] {8-\epsilon}-2|<|x-2|<|\sqrt[3] {8+\epsilon}-2|$$...
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    Direction and magnitude of electric field produced by current change

    I am actually asking whether it is ##-\frac{\mu_o abN}{2L}## or ##-\frac{\mu_o abN^2}{2L}## but I think now I know why I am wrong. I was mistaken when taking which object to consider. I thought I need to consider the number of turns of solenoid. It turns out I need to consider the loop...
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    Direction and magnitude of electric field produced by current change

    For electric field in question (b), the correct answer is ##-\frac{\mu_o abn}{2}## or ##-\frac{\mu_o abnN}{2}##? Thanks
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    Direction and magnitude of electric field produced by current change

    I mean why for the flux it is not ##\frac{\mu_o N^2 I}{L}##. I saw something similar to this when calculating self inductance of solenoid; I need to multiply the flux to get total flux linkage so the self inductance can be ##\frac{\mu_o N^2 \pi r^2}{L}## I understand
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    Direction and magnitude of electric field produced by current change

    The answer key is: a) ##\frac{\mu_o \pi nar_{1}^{2}}{R}## b) ##-\frac{\mu_o abn}{2}## My questions: 1) Why is there no ##\cos \theta## in answer (a)? $$\text{induced current}=\frac{\varepsilon}{R}$$ When calculating induced emf ##\varepsilon=-\frac{d\Phi}{dt}=-\frac{d(\vec B . \vec A)}{dt}##...
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    Solving the wave equation with piecewise initial conditions

    I am really sorry for late reply I think I get this. Thank you very much for all the help and explanation Orodruin, pasmith, WWGD, Gavran
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