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Question:

Homework Statement An observable ##\hat{A}## is represented by the matrix $$A = \lambda \begin{pmatrix} 0 & 1 & 0\\ 1 & 0 & 0\\ 0 & 0 & 2 \end{pmatrix}$$ (a) Find the eigenvalues and eigenvectors of ##A## (b) Suppose that the system starts out in the generic state $$| S(0) \rangle = \begin{pmatrix} c_1 \\ c_2 \\ c_3 \end{pmatrix} $$ with ## |c_1|^2 + |c_2|^2 + |c_3|^2 = 1##. Find the expectation values (at ##t==0##) of ##\hat{A}##. (c) What is ##| S(t) \rangle ##? If you measured ##\hat{A}## at time ##t##, what values might you get , and what is the probability of each? Relevant Equations ##\langle \hat{A} \rangle = \langle \Psi | \hat{A} | \Psi \rangle## The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways to solve (b). The easiest is $$\langle \hat{A} \rangle = \langle S(0) | \hat{A} | S(0) \rangle = \lambda \begin{pmatrix} c_1^* & c_2^* & c_3^*\\ \end{pmatrix} \begin{pmatrix} 0 & 1 & 0\\ 1 & 0 & 0\\ 0 & 0 & 2 \end{pmatrix} \begin{pmatrix} c_1 \\ c_2 \\ c_3 \end{pmatrix} = 2 \lambda |c_3|^2 + \lambda c_1^*c_2 + \lambda c_2^*c_1 $$ But I have done a problem similar to this earlier in the textbook so I "anticipated" what I thought I might need. So I wrote: $$| S(0) \rangle = c_3 \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} + \frac{c_1 + c_2}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ 1/ \sqrt{2} \\ 0 \end{pmatrix} + \frac{c_1 - c_2}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ -1/ \sqrt{2} \\ 0 \end{pmatrix} $$ We have written the state as a sum of eigenvectors, which means that we can write $$\langle \hat{A} \rangle = 2 \lambda |c_3|^2 + \lambda \bigg|\frac{c_1 + c_2}{\sqrt{2}}\bigg|^2 - \lambda \bigg|\frac{c_1 - c_2}{\sqrt{2}}\bigg|^2 = 2 \lambda |c_3|^2 + \lambda c_1^*c_2 + \lambda c_2^*c_1$$ Part (c) is where I am having problems. In a previous example the author just "tacks on the time wiggle factor" $$| S(t) \rangle = c_3 \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} e^{-2i\lambda t / h} + \frac{c_1 + c_2}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ 1/ \sqrt{2} \\ 0 \end{pmatrix} e^{-i\lambda t / h} + \frac{c_1 - c_2}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ -1/ \sqrt{2} \\ 0 \end{pmatrix} e^{i\lambda t / h} $$ The possible values we can get are the eigenvalues of ##A##. The probability of obtaining each is the squared magnitude of the coefficient of the corresponding eigenvector. This is not correct. From looking at the solution it appears that we make something like the following map: $$ \begin{pmatrix} c_1 \\ c_2 \\ c_3 \end{pmatrix} \rightarrow \begin{pmatrix} c_1e^{-i \lambda t /h} \\ c_2 e^{i \lambda t /h}\\ c_3 e^{-2i \lambda t /h} \end{pmatrix} $$ I say "something like" because I don't understand how you choose which "time-wiggle-factor" to apply to which ##c_i##. Making this substitution we get closer to the solution $$| S(t) \rangle = c_3 e^{-2i\lambda t / h} \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} + \frac{c_1 e^{-i\lambda t / h} + c_2 e^{i\lambda t / h}}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ 1/ \sqrt{2} \\ 0 \end{pmatrix} + \frac{c_1 e^{-i\lambda t / h} - c_2 e^{i\lambda t / h}}{\sqrt{2}} \begin{pmatrix} 1/ \sqrt{2} \\ -1/ \sqrt{2} \\ 0 \end{pmatrix} $$ That is, the square magnitude of the coefficients of eigenvectors look a lot more like the corresponding probabilities in the solution. So if it is the case that by "tacking on" the time-wiggle factors, we tack the time-wiggle factor onto each component of the initial state vector, that makes perfect sense to me. But how do decide which wiggle factor to tack onto which coordinate of ##| S(0) \rangle##??

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Homework
4 months ago
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Question:

1 Makerere University Department of Electrical and Computer Engineering B.Sc. in Electrical Engineering, B.Sc. in Computer & Communications Engineering and B.Sc. Biomedical Engineering EMT1101 – ENGINEERING MATHEMATICS I Coursework Set 1 Instructions: a) Work in groups of 2–3 members. b) Each group must include members from different programmes (BELE, BCCE, BBI). c) Clearly list each member’s name, registration number, and programme on the cover page. d) Solutions may be handwritten or typed. e) Submission deadline: 30th October 2025 at 8:00 AM (strictly). 1. For power system engineers, it is essential to ensure maximum power transfer from the source to the load. Figure 1 shows a circuit in which a non-ideal voltage source is connected to a variable load resistor with resistance 𝑅𝐿. The source voltage is 𝑉 and its internal resistance is 𝑅𝑆. Calculate the value of 𝑅𝐿 which results in the maximum power being transferred from the voltage source to the load resistor. 6 Marks Figure 1 2. Find the dimensions of the right-circular cylinder of largest volume that can be inscribed in a sphere of radius R. 4 Marks 3. Sketch graphs of the functions 2 (i) 𝑦 = 𝑥2−𝑥−6 𝑥+1 5 Marks (ii)𝑦 = 𝑥−1 𝑥2−4 5 Marks 4. Given the system of linear equations 4𝑥 − 5𝑦 + 7𝑧 = −14 9𝑥 + 2𝑦 − 3𝑧 = 47 𝑥 − 𝑦 − 5𝑧 = 11 Solve the equation using (i) Crammer’s rule 5 Marks (ii)Gauss elimination method 5 Marks 5. (a) Sketch graphs of the following functions (i) 𝑓(𝑥) = 𝑥 |𝑥| 2 Marks (ii) 𝑓(𝑥) = √4 − 𝑥2 2 Marks (iii)𝑓(𝑥) = {𝑥2, 𝑥 > 1 2, 𝑥 ≤ 1 2 Marks (b) An open box is to be made from an 8𝑐𝑚 × 15𝑐𝑚 piece of sheet metal by cutting out squares with sides of length 𝑥 from each of the four corners and bending up the sides. Express the volume 𝑉 of the box as a function 𝑥, and state the domain and range of the function. 4 Marks 6. Evaluate the following integrals (i) ∫ sin2 3𝑥 cos 3𝑥 𝑑𝑥 𝜋 2 ⁄ 0 4 Marks (ii) ∫ cos 2𝑥 √7−3 sin 2𝑥 𝑑𝑥 𝜋 4 ⁄ 0 4 Marks (iii)∫ 𝑥2 √4−3𝑥 𝑑𝑥 1 0 4 Marks (iv) ∫ √tan 𝑥 sec2 𝑥 𝑑𝑥 4 Marks (v) ∫ 𝑒𝑎𝑥 cos 𝑏𝑥 𝑑𝑥 4 Marks

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Homework
6 months ago
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Question:

Which of the following sets are equal? A = {x | x^2 − 4x + 3 = 0}, C = {x | x ∈ N, x < 3}, E = {1, 2}, G = {3, 1}, B={x|x^2−3x+ 2 = 0}, D = {x|x∈N, x is odd, x<5}, F={1,2,1}, H={1,1,3}. Hint: for the quadratic Equations, get the values of x which shall be elements of set A and B.) 2. List the elements of the following sets if the universal set is U = {a, b, c, ..., y, z}. Furthermore, identify which of the sets, if any, are equal. A = {x |x is a vowel}, C = {x |x precedes f in the alphabet}, B = {x |x is a letter in the word “little”}, D = {x |x is a letter in the word “title”}. 3. Let A= {1,2,...,8,9}, B={2,4,6,8}, C={1,3,5,7,9}, D={3,4,5}, E={3,5}. Which of the these sets can equal a set X under each of the following conditions? (a) X and B are disjoint. (c) X⊆A but X ⊈ C. (b) X ⊆ D but X ⊈ B. (d) X⊆C but X ⊈ A. 4. Consider the universal set U = {1,2,3,...,8,9} and sets A={1,2,5,6}, B={2,5,7}, C={1,3,5,7,9}. Find: (a) A∩B and A∩C (b) A∪B and B∪C (d)A\BandA\C (f)(A∪C)\Band(B⊕C)\A (c)AC and CC (e) A⊕B and A⊕C 5. The formula A\B = A ∩ B C defines the difference operation in terms of the operations of intersection and complement. Find a formula that defines the union A ∪ B in terms of the operations of intersection and complement. 6. The Venn diagram in Fig. (a) shows sets A, B, C. Shade the following sets: (a) A\(B∪C); (b)AC∩(B∪C); (c)AC∩(C\B). ( Note you can draw different diagram for each answer to avoid shading overlapping and congestion.) 7. Write the dual of each equation: (a) A=(BC∩A)∪(A∩B) (b) (A∩B)∪(AC∩B)∪(A∩BC)∪(AC∩BC)=U 8. Use the laws in Table 1 - 1 to prove each set identity: (a) (A∩B)∪(A∩BC) = A (b) A∪B=(A∩BC)∪(AC∩B)∪(A∩B) Section Two 9. Determine which of the following sets are finite: (a) Lines parallel to the x axis. (c) Integers which are multiples of 5. (b) Letters in the English alphabet. (d) Animals living on the earth. 1 10. A survey on a sample of 25 new cars being sold at a local auto dealer was conducted to see which of three popular options, air-conditioning (A), radio (R), and power windows (W ), were already installed. The survey found: 15 had air-conditioning (A), 12 had radio (R), 11 had power windows (W), 5 had A and P , 9 had A and R, 3 had all three options. 4 had R and W, Find the number of cars that had:(a) only W; (b) only A; (c) only R; (d) R and W but not A; (e) A and R but not W; (f) only one of the options; (g) at least one option; (h) none of the options. 11. Find the power set P(A) of A={1,2,3,4,5}. 12. Given A = [{a,b},{c},{d,e,f}]. (a) List the elements of A. (b) Find n(A). (c) Find the power set of A. 13. Let S = {1, 2, ..., 8, 9}. Determine whether or not each of the following is a partition of S : (a) [{1,3,6},{2,8},{5,7,9}] (b) [{1,5,7},{2,4,8,9},{3,5,6}] (c) [{2,4,5,8},{1,9},{3,6,7}] (d) [{1,2,7},{3,5},{4,6,8,9},{3,5}]

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Homework
8 months ago
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Question:

LINEAR ALGEBRA II: Assignment No.2(Sets, Relations and Functions). AUGUST 2025: Date of Submission Wednesday 3rd September, 2025: mode of submission – hard copy or email @ willyacadamia2019@gmail.com. Section One 1. Which of the following sets are equal? A = {x | x2 − 4x + 3 = 0}, C = {x | x ∈ N, x < 3}, E = {1, 2}, G = {3, 1}, B={x|x2−3x+2=0}, D = {x|x∈N, x is odd, x<5}, F={1,2,1}, H={1,1,3}. Hint: for the quadratic Equations, get the values of x which shall be elements of set A and B.) 2. List the elements of the following sets if the universal set is U = {a, b, c, ..., y, z}. Furthermore, identify which of the sets, if any, are equal. A = {x |x is a vowel}, C = {x |x precedes f in the alphabet}, B = {x |x is a letter in the word “little”}, D = {x |x is a letter in the word “title”}. 3. Let A= {1,2,...,8,9}, B={2,4,6,8}, C={1,3,5,7,9}, D={3,4,5}, E={3,5}. Which of the these sets can equal a set X under each of the following conditions? (a) X and B are disjoint. (c) X⊆A but X ⊈ C. (b) X ⊆ D but X ⊈ B. (d) X⊆C but X ⊈ A. 4. Consider the universal set U = {1,2,3,...,8,9} and sets A={1,2,5,6}, B={2,5,7}, C={1,3,5,7,9}. Find: (a) A∩B and A∩C (b) A∪B and B∪C (d)A\BandA\C (f)(A∪C)\Band(B⊕C)\A (c)AC and CC (e) A⊕B and A⊕C 5. The formula A\B = A ∩ B C defines the difference operation in terms of the operations of intersection and complement. Find a formula that defines the union A ∪ B in terms of the operations of intersection and complement. 6. The Venn diagram in Fig. (a) shows sets A, B, C. Shade the following sets: (a) A\(B∪C); (b)AC∩(B∪C); (c)AC∩(C\B). ( Note you can draw different diagram for each answer to avoid shading overlapping and congestion.) 7. Write the dual of each equation: (a) A=(BC∩A)∪(A∩B) (b) (A∩B)∪(AC∩B)∪(A∩BC)∪(AC∩BC)=U 8. Use the laws in Table 1-1 to prove each set identity: (a) (A∩B)∪(A∩BC) = A (b) A∪B=(A∩BC)∪(AC∩B)∪(A∩B) Section Two 9. Determine which of the following sets are finite: (a) Lines parallel to the x axis. (c) Integers which are multiples of 5. (b) Letters in the English alphabet. (d) Animals living on the earth. 1 10. A survey on a sample of 25 new cars being sold at a local auto dealer was conducted to see which of three popular options, air-conditioning (A), radio (R), and power windows (W ), were already installed. The survey found: 15 had air-conditioning (A), 12 had radio (R), 11 had power windows (W), 5 had A and P , 9 had A and R, 3 had all three options. 4 had R and W, Find the number of cars that had:(a) only W; (b) only A; (c) only R; (d) R and W but not A; (e) A and R but not W; (f) only one of the options; (g) at least one option; (h) none of the options. 11. Find the power set P(A) of A={1,2,3,4,5}. 12. Given A = [{a,b},{c},{d,e,f}]. (a) List the elements of A. (b) Find n(A). (c) Find the power set of A. 13. Let S = {1, 2, ..., 8, 9}. Determine whether or not each of the following is a partition of S : (a) [{1,3,6},{2,8},{5,7,9}] (b) [{1,5,7},{2,4,8,9},{3,5,6}] (c) [{2,4,5,8},{1,9},{3,6,7}] (d) [{1,2,7},{3,5},{4,6,8,9},{3,5}] Section Three 14. Prove : 2+4+6+···+2n = n(n+1) Using Mathematical Induction 15. Let S={a,b,c},T={b,c,d}, and W={a,d}. Find S×T×W. 16. Find x and y where: (a)(x+2,4)= (5,2x+y); (b)(y−2, 2x+1)= (x−1, y+2). 17. Prove: A×(B∩C)=(A×B)∩(A×C) 18. Consider the relation R = {(1, 3), (1, 4), (3, 2), (3, 3), (3, 4)} on A = {1, 2, 3, 4}. (a) Find the matrix MR of R. (b) Find the domain and range of R. (c) Find R−1. (d) Draw the directed graph of R. 19. Determine if each function is one-to-one. (a) To each person on the earth assign the number which corresponds to his age. (b) To each country in the world assign the latitude and longitude of its capital. (c) To each book written by only one author assign the author. (d) To each country in the world which has a prime minister assign its prime minister. 20. Let functions f,g,h from V ={1,2,3,4} into V be defined by :f(n)= 6−n, g(n)=3, h = {(1, 2), (2, 3), (3, 4), (4, 1)}. Decide which functions are: (a) one-to-one; (b) onto; (c) both; (d) neither. 21. Prove Theorem 3.1: A function f : A → B is invertible if and only if f is both one-to-one and onto. 22. Find the cardinal number of each set: (a) {x | x is a letter in “BASEBALL”}; (b) Power set of A = {a,b,c,d,e}; (c) {x |x2 = 9,2x = 8}. 2

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Homework
8 months ago
1
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