Recent content by TadeusPrastowo

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    [Compound Interest] Layman way vs. Derivative way

    That makes sense. Ah, I see the point now. Thank you very much.
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    [Compound Interest] Layman way vs. Derivative way

    Taking an analogy to instantaneous rate-of-change of car's position (i.e., car's speed), the rate-of-change of position is very beneficial because speed relates to the magnitude of the car's kinetic energy where the greater the energy is, the more fatal a car crash becomes. So, I think the...
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    [Compound Interest] Layman way vs. Derivative way

    My https://www.amazon.com/dp/0073532320/?tag=pfamazon01-20 (p. 176 Example 7.1) pointed out that an investment ##p(t) = 100\,2^t## (##t## in year) that doubles the capital every year starting with an initial capital of $100, has an (instantaneous) rate-of-change ##\frac{\text{d}}{\text{d}t} p(t)...
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    [Limit] Algebraic Manipulation of Rational Function

    Now I understand. Thank you very much for your patience. I took a look again at the formal definition of limit as ##x## grows unbounded and saw that indeed the requirement for ##\lim_{x\to \infty} f(x)## to exist is to have a horizontal asymptote, not a slant asymptote (i.e., a slant asymptote...
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    [Limit] Algebraic Manipulation of Rational Function

    Specifically, I want to know the sound method to algebraically manipulate a rational function definition in finding the equation of the asymptote as ##x## grows without bound. For example: 1. Always start with a long division because of this reason. 2. Then, for the resulting terms, divide by...
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    [Limit] Algebraic Manipulation of Rational Function

    I don't agree. In my opinion, analytically, as ##x## gets very large, the algebraic manipulation of the function definition must reveal the nature of the asymptote: whether it is horizontal or slanted. As the numerical calculation shows that my alternative obtained by extracting the greatest...
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    [Limit] Algebraic Manipulation of Rational Function

    My https://www.amazon.com/dp/0073532320/?tag=pfamazon01-20 gives a rule of thumb to divide by the highest power in the denominator for the following problem to demonstrate a slant (oblique) asymptote: \lim_{x\to\infty} \frac{4x^3+5}{-6x^2-7x} = \lim_{x\to\infty}...
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    Limit epsilon-delta definition vs. continuity

    Many many many thanks for pointing out the concept of being connected vs. being disconnected to me. Yes, that's exactly what I want to say by my word "gapless". Once again, thank you very much. I really appreciate your enlightenment.
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    Limit epsilon-delta definition vs. continuity

    In my own words, by "gapless" I mean a domain such as the set ##\mathbb{R}## of real numbers. ##\mathbb{R} = \mathbb{Q} \bigcup \overline{\mathbb{Q}}##. That is, for any gap between the closest pair of rational numbers, there are infinitely many irrational numbers filling in the gap making the...
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    Limit epsilon-delta definition vs. continuity

    Based on the following problem from http://math.uchicago.edu/~vipul/teaching-0910/151/applyingformaldefinitionoflimit.pdf: f(x) = \begin{cases} x^2 &, \text{ if }x\text{ is rational} \\ x &, \text{ if } x\text{ is irrational} \end{cases} is shown to have the following limit: \lim_{x\to 1}f(x)...
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    Finding rate of change of moment of inertia tensor

    I have tried to continue the derivation after correcting the dr/dt as you pointed out. I did (\boldsymbol\omega \times \mathbf{r}_p)_k by calculating \boldsymbol\omega \times \mathbf{r}_p first as matrix multiplication [\omega]_\times [r_p] and then taking the k-element. Then, I continued...
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    Finding rate of change of moment of inertia tensor

    No, it is not \boldsymbol\omega \times \boldsymbol\omega but \boldsymbol\omega \times [I] \boldsymbol\omega where [I] is a second-order tensor, not a scalar. To be exact, we are dealing with the product of matrices [\omega]_\times \left([I] [\omega]\right). See Wikipedia article on cross-product...
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    Finding rate of change of moment of inertia tensor

    Homework Statement The Wikipedia article on spatial rigid body dynamics derives the equation of motion \boldsymbol\tau = [I]\boldsymbol\alpha + \boldsymbol\omega\times[I]\boldsymbol\omega from \sum_{i=1}^n \boldsymbol\Delta\mathbf{r}_i\times (m_i\mathbf{a}_i). But, there is another way to...
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    Tensor differentiation (element-by-element)

    Homework Statement Proof the following: \frac{\text{d}\boldsymbol\{\mathbf{I}\boldsymbol\}}{\text{d}t} \, \boldsymbol\omega = \boldsymbol\omega \times (\boldsymbol\{\mathbf{I}\boldsymbol\}\,\boldsymbol\omega) where \boldsymbol\{\mathbf{I}\boldsymbol\} is a tensor...
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    Angular Momentum Contradiction Due To Choice Of Origin

    Ah, yes, you are right about it, haruspex! Thank you very much!
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