diff --git a/Fall-2024/CS-3113/Lessons/lesson_0.pdf b/Fall-2024/CS-3113/Lessons/lesson_0.pdf new file mode 100644 index 0000000..b54a256 Binary files /dev/null and b/Fall-2024/CS-3113/Lessons/lesson_0.pdf differ diff --git a/Fall-2024/CS-3113/Lessons/lesson_1.pdf b/Fall-2024/CS-3113/Lessons/lesson_1.pdf new file mode 100644 index 0000000..c8df838 Binary files /dev/null and b/Fall-2024/CS-3113/Lessons/lesson_1.pdf differ diff --git a/Fall-2024/CS-3113/Lessons/lesson_2.pdf b/Fall-2024/CS-3113/Lessons/lesson_2.pdf new file mode 100644 index 0000000..a2aa9d7 Binary files /dev/null and b/Fall-2024/CS-3113/Lessons/lesson_2.pdf differ diff --git a/Fall-2024/CS-3113/Lessons/lesson_3.pdf b/Fall-2024/CS-3113/Lessons/lesson_3.pdf new file mode 100644 index 0000000..bcd79a4 Binary files /dev/null and b/Fall-2024/CS-3113/Lessons/lesson_3.pdf differ diff --git a/Fall-2024/CS-3113/Lessons/lesson_4.pdf b/Fall-2024/CS-3113/Lessons/lesson_4.pdf new file mode 100644 index 0000000..d6a09de Binary files /dev/null and b/Fall-2024/CS-3113/Lessons/lesson_4.pdf differ diff --git a/Fall-2024/CS-3333/Assignments/1/HW1.typ b/Fall-2024/CS-3333/Assignments/1/HW1.typ new file mode 100644 index 0000000..fb03ade --- /dev/null +++ b/Fall-2024/CS-3333/Assignments/1/HW1.typ @@ -0,0 +1,74 @@ +#set page(margin: (x: .5in, y: .5in)) +#let solve(solution) = [ + #let solution = align( + center, + block( + inset: 5pt, + stroke: blue + .3pt, + fill: rgb(0, 149, 255, 15%), + radius: 4pt, + )[#align(left)[#solution]], + ) + #solution +] +#align(center)[ + = CS 3333 Mathematical Foundations + Homework 1 (100 points)\ + #underline[Price Hiller] *|* #underline[zfp106] +] + +*Submission:* ++ Submit a single PDF (not Word) file through Canvas. ++ You can either edit the Word file directly or write down your solution in any other text document using other editors. ++ Convert the Word document or the text document into a single PDF file. ++ If there is any plagiarism, you will lose all points on the questions at first time. In next, you will lose all points in the whole homework. +#line(length: 100%, stroke: .25pt) + +*Questions:* +1. Does 41 divide each of these numbers (just answer yes or no)? (16 points) +#solve[#align(center)[]#grid( + columns: (100pt, 100pt), + rows: (10pt, auto), + gutter: 3pt, + [a) 123 *(yes)*], [b) 92 *(no)*], + [c) 413 *(no)*], [d) 1640 *(yes)*], + )] + +2. Prove/Show that if $a | b$ and $b | a$, where $a$ and $b$ are integers, then $a = b$ or $a = -b$. (20 points) + #solve[ + + $b = a k$, where $k$ is an integer + + $a = b q$, where $q$ is an integer + + Use $a = b q$ + + Substitute $b$: $a = a k q$ + + Algebra: $k q = 1$ + + ∵ $k$ & $q$ are integers, $k$ and $q$ must be $1$ or $-1$ + + ∴ $a = b$ or $a = -b$ + ] + +3. Prove that if $a$, $b$, $c$, and $d$ are integers, where $a ≠ 0$ and $b ≠ 0$, such that $a | c$ and $b | d$, then $a b | c d$. (20 points) + #solve[ + + $c = k a$, where $k$ is an integer + + $d = q b$, where $q$ is an integer + + $c d = (k a)(q b) = (k q)(a b)$ + + $a b | (k q)(a b)$ is true + + ∴ $a b | c d$ + ] + +4. When $x$ is an integer, prove that $1 + x^2 <= (1 + x)^2$ is true or disprove it by providing a counterexample. (20 points) + #solve[ + + False. Counterexample: let $x = -1$ + + Substitute $x$: $1 + (-1)^2 <= (1 + (-1))^2$ + + Solve: $2 <= 0$, not true + + ∴ when $x$ is an integer $1 + x^2 <= (1 + x)^2$ is false + ] + +5. Prove that if $a$ is an integer that is not divisible by $3$, denoted as $3 ∤ a$, then $(a + 1)(a + 2)$ is divisible by $3$, denoted as $3 | (a + 1)(a + 2)$. (24 points) + #solve[ + + Prove: $3 | (a + 1)(a + 2)$ + + Assume $a = 3k + 1$, where $k$ is an integer + + Substitute $a$: $((3k + 1) + 1)((3k + 1) + 2)$ + + Algebra: $9k^2 + 15k + 6$ + + Factor $3$: $3(3k^2 + 5k + 2)$ + + $3$ times some integer is necessarily divisible by $3$ according to divisibility + + ∴ If $3 ∤ a$, then $3 | (a + 1)(a + 2)$ + ]