Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: THEend8_
Instructions
There are a total of 9 questions, consisting of a total of 100 marks.
The assignment should be submitted as a single PDF document through Canvas by the due date. The assignment can be either handwritten or typed on A4 size sheets, and must be submitted as a pdf. If you hand-write, a recommended app to convert to pdf is ‘camscanner’, but any method that gives a reasonably sized pdf is fine.
Remember to include your name and ID number clearly in what you submit.
Remember to upload the signed and dated cover sheet.
All working must be given for all questions, even if the question does not specifically ask for it. If a question does not ask for a particular method of solution, any method we have covered in class is fine. Unless specifically mentioned, questions must be worked out by hand, not on a computer.
This is an individual assignment, although you are encouraged to work together with others to discuss questions and come up with general strategies for solutions, what you hand in must be your own work.
Late assignments, without an approved extension, will be subject to a deduction of 5% (one grade e.g. from C+ to C) of the total mark available for each 24-hour period, or part thereof, up to a maximum of five calendar days. Assignments over five days late will not normally be accepted or marked and students will receive a DNC (Did Not Complete) for that assessment. You may find more information from the URL link: https://student.aut.ac.nz/study/study-help/assessments-and-exams
Question 1 (10 marks) Use truth tables to show the following:
(a) whether →p Λ → (p → →q) is a tautology, a contradiction or neither.
(b) whether ((p → q) Λ (p → r)) → (p → (q Λ r)) is a tautology, a contradiction or neither.
(c) → (→p Λ q) and q → p are logically equivalent.
(d) ((p → r) Λ (q → r)) Λ →r and → ((p V q) V r) are logically equivalent.
Question 2 (10 marks) Use laws of logic to show the following equivalences (clearly indicate which law you use in each step):
(a) → (→p Λ q) ≡ (q → p) .
(b) ((p → r) Λ (q → r)) Λ →r ≡ → ((p V q) V r)
Question 3 (10 marks) Using Euclid’s algorithm, determine if the following rational numbers are in re- duced form. If not, write down their reduced forms. Show your working.
(a) 76/180
(b) 53/223
Question 4 (10 marks) Prove the following statements.
(a) For all n ∈ Z, n3 + 3n2 + 2n ≡ 0 (mod 3).
(b) For all n ∈ Z, n3 + 3n + 2 is even.
Question 5 (20 marks) Prove or disprove the following as directed:
(a) Prove the following by direct proof:
Let a ∈ Z, if a ≡ 1 (mod 7), then a2 ≡ 1 (mod 7) .a2 ≡ 1 (mod 7)
(b) Prove the following by contraposition (using the contrapositive): For all n ∈ Z, if n2 is even, then n is even.
(c) Disprove the following by finding counterexamples:
For all integers a,b, if a + b is even then both a and b are even.
Let A, B and C be sets. If A × C = B × C, then A = B .
(d) Prove by induction that 2n + 1 ≤ 2n for all integers n ≥ 5.
(e) Prove the following by induction:
n2 < 2n for all integers n ≥ 5. Make use of the result in the previous part.
Question 6 (10 marks) Let A = {1, 4, 5, 6}, B = {2, 3, 4, 5}, C = {1, 2, 3}. Show the following sets by enumeration:
(a) {x | x ∈? A,x ∈ B and x|24}
(b) {X | X ? A and |X| = 2}
(c) {X | X ? A and 4 ∈ X}
(d) {X | X ? B and X ∩ A ?}
(e) The power set of C.
Question 7 (10 marks) Let U,A,B, C be as indicated in the Venn diagram below:
Shade the areas of following sets in Venn diagrams.
(a) (A ∩ B) ∩ C
(b) A ∩ (B ∩ C)
(c) A ∪ C ∩ B
(d) A ∪ (B ∪ C))
Question 8 (10 marks) Diet Survey
In a survey of 99 individual students regarding diet, the following data were obtained:
57 eat apples.
45 eat broccoli.
56 eat cheese.
22 eat apples and broccoli.
25 eat apples and cheese.
27 eat broccoli and cheese.
5 do not eat any of these three foods.
(a) Represent this problem in a Venn diagram, and shade the set of students who eat only one of the three foods.
(b) How many students eat only one of the three foods? (Hint: you may want to first figure out how many students eat all three foods.) Show your working.
Question 9 (10 marks) Use set operation laws to show the following set equality. Clearly indicate which law you use in each step.