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Chapter 17: Exam

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    212862
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    Part I (Practice, 4 hours)

     

    Problem 1

    Let \(U=\left\{\frac{1}{3^{n^2}}\right\}_{n\in \mathbb{N}_0}\) and \(\mathbb{T}=(1-U)\cup (1+U)\cup \{2\}\cup (2+U)\).

     

    1. Prove that \(\mathbb{T}\) is a time scale.

    2. Find the forward jump operator \(\sigma\).

    3. Find the backward jump operator \(\rho\).

    4. Classify each points of \(\mathbb{T}\).

    5. Find the forward graininess function \(\mu\).

    6. Find the backward graininess function \(\nu\).

    7. Find \(\sigma^2(\rho(t))\) for \(t\in (1-U)\).

    8. Find \(\mu(t)-\nu(t)\rho^3(\sigma^2(t))\) for \(t\in (2+U)\).

    9. Simplify

    \[A(t)= \left(\frac{5\sigma(t)-2(\sigma(t))^2}{(\sigma(t)-2)^2}+\sigma(t)\right): \left(\sigma(t)-\frac{3\sigma(t)-8}{(\sigma(t)-2)^2}-2\right), \quad t\in \mathbb{T},\quad \sigma(t)\ne 2.\notag\] 

    10. Check if the following inequality is true

    \[\sigma^4(t)\rho^2(t)-\rho^3(t)+(\mu(t))^2-t\leq \sigma(t),\quad t\in (1-U).\notag\]

     

    Problem 2

    Let \(\mathbb{T}=2^{\mathbb{N}_0}\cup \left(\frac{1}{3}\right)^{\mathbb{N}_0}\cup 4\mathbb{Z}\) and

    \[ f(t)= \frac{a+bt+ct^2}{d+kt},\quad t\in \mathbb{T},\notag\]

    where \(a, b, c, d, k\) are real parameters.

    1. For \(a=0, b=1, c=3, d=-1, k=3\), find

    \[ f^\rho(t)-f^{\sigma^2\rho^3}(t),\quad t\in \left(\frac{1}{3}\right)^{\mathbb{N}_0}.\notag\]

    2.  For \(a=-1, b=0, c=1, d=3, k=2\), find

    \[ f^{\sigma^2}(t),\quad t\in 2^{\mathbb{N}_0}.\notag\]

    3.  For \(a=2, b=3, c=-4, d=1, k=-1\), check if the function is rd-continuous.

    4.   For \(a=-5, b=-1, c=1, d=0, k=4\), check if the function is ld-continuous.

    5.   For \(a=-\frac{1}{3}, b=2, c=0, d=-1, k=5\), check if the function is continuous.

    6.   For \(a=2, b=-1, c=2, d=-3, k=1\), check if the function is rd-regulated.

    7.   For \(a=23, b=1, c=0, d=5, k=1\), check if the function is predifferentiable.

    8.   For \(a=-10, b=1, c=2, d=3, k=2\), check if the function is regressive.

    9.   For \(a=15, b=0, c=4, d=-1, k=1\), check if the function is ld-regulated.

    10.   For \(a=-2, b=1, c=3, d=10, k=1\), find

    \[(f(t)\oplus_\mu \sigma(t))\ominus_\nu \rho(t),\quad t\in 4\mathbb{Z}.\notag\]

     

     

    Problem 3

     

    Let \(\mathbb{T}=\left(\frac{1}{2}\right)^{\mathbb{N}_0}\cup 4^{\mathbb{N}_0}\) and

    \[\begin{aligned}f(t)=& 2-3t+4t^2-t^3,\\g(t)=& \frac{1+2t}{2+7t},\quad t\in \mathbb{T}.\end{aligned}\notag\]

    1. Find \(f^\Delta(t)\) for \(t\in \left(\frac{1}{2}\right)^{\mathbb{N}_0}\).

    2. Find \(f^{\nabla^2}(t)\) for \(t\in 4^{\mathbb{N}_0}\).

    3. Find \(\left(\frac{f}{g}\right)^\Delta(t)\) for \(t\in \left(\frac{1}{2}\right)^{\mathbb{N}_0}\).

    4. Find \((fg)^\nabla(t)\) for \(t\in 4^{\mathbb{N}_0}\).

    5. Find the region of delta differentiation of the function f in \(\left(\frac{1}{2}\right)^{\mathbb{N}_0}\).

    6. Find the region of nabla differentiation of the function \(g\) in \(4^{\mathbb{N}_0}\).

    7. Find the regions of increasing of the function \(f\) over the whole time scale \(\mathbb{T}\).

    8. Find the regions of decreasing of the function \(f\) in \(4^{\mathbb{N}_0}\).

    9. Investigate for convexity the function \(f-g\) over the whole time scale \(\mathbb{T}\).

    10. Investigate for concavity the function \(fg\) over the whole rime scale \(\mathbb{T}\) and investigate it for local extremum points.           

     

     

    Problem 4

    Let \(\mathbb{T}=(-5\mathbb{N}_0)\cup 4^{\mathbb{N}_0}\) and

    \[f(t)=\begin{cases} 3t^2+15t+25\quad \mbox{if}\quad t\in (-5\mathbb{N})\\ 1\quad \mbox{if}\quad t=0\\ 21t^2\quad \mbox{if}\quad t\in 4^{\mathbb{N}_0}\end{cases}\notag\]

    and

    \[ g(t)=at^2+bt+c,\quad t\in \mathbb{T},\notag\]

    where \(a, b, c\) are real parameters.

    1. Using the definition for delta integral, prove that

    \[\int f(t)\Delta t=t^3+d,\quad t\in \mathbb{T},\notag\]

    where \(d\) is a constant.

    2. For \(a=-1, b=2, c=3\), find

    \[\int\limits_{-10}^{64}g(t)\Delta t.\notag\]

    3. Find

    \[\int\limits_{-625}^0 f(t)\nabla t.\notag\]

    4.  Check the rule for integration by parts for the functions \(f\) and \(g\) in \(4^{\mathbb{N}_0}\) for \(a=1, b=0, c=-3\).

    5. For \(a=1, b=-2, c=1\), investigate for convergence the integral

    \[\int\limits_0^{16}\frac{1}{g(t)}\Delta t.\notag\]

    6. For \(a=2, b=3, c=-1\) write the Taylor formulae to the fourt term for the function \(g\).

    7. For \(a=2, b=-3, c=1\), find

    \[\int\limits_{-5}^{16}g(t)h_2(t, -5)\Delta t,\notag\]

    where \(h_2\) is the generalized time scales monomial.

    8. For \(a=1, b=3, c=2\), find

    \[\int\limits_1^{64}(e_2(t, 1)-\sinh_3(t, 1)-3g(t))\Delta t. \notag\]

    9. For \(a=0, b=0, c=2\), find

    \[\int_{-10}^1 (g(t)e_1(t, -10)-h_2(t, -10))  \Delta t.\notag\]

    10. For \(a=3, b=0, c=10\), find

    \[\int_1^{128}\left((g(t))^2-f(t)\right)\Delta t.\notag\] 

     

     

    Part II (Theory, 4 hours)

    Question 1

    Formulate and prove the dual induction principle.

    Question 2

    Give a definition for first order nabla derivative and prove that the definition is correct.

    Question 3

    Prove the rule for delta differentiation of  product of two functions.

    Question 4

    Give an example for a forward jump operator that is not continuous.

    Question 5

    Formulate and prove the Rolle theorem in the nabla case.

    Question 6

    Give a definition for a completely delta differentiable function and formulate and prove a criterion for completely delta differentiablity  of a function.

    Question 7

    Formulate and prove the first mean value theorem.

    Question 8

    Give a definition for Riemann delta integrable function.

    Question 9

    Formulate and prove the Cauchy criterion for Riemann nabla integrability of a function.

    Question 10

    Give definitions for the monomials \(h_k\) and \(g_k\) and  deduct a relation between them.

     


    This page titled Chapter 17: Exam is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Svetlin G. Georgiev.

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