7/Show that any positive odd integer is of the form (4m + 1) or (4m +3)
where m is some integer.
Answers
Answer!
Let a be any odd positive integer and b = 4. By division lemma there exist integer q and r such that
a = 4 q + r, where 0 ≤ r ≤ 4
so a = 4q or, a = 4q + 1 or, a = 4q + 2 or, a = 4q + 3
4q + 1 → 4 is divisible by 2 but 1 is not divisible by 2, so it is an odd number
4q + 2 → 4 is divisible by 2 and 2 is also divisible by 2, so it is an even number
4q + 3 → 4 is divisible by 2 but 3 is not divisible by 2, so it is an odd number
4q + 4 → 4 is divisible by 2 and 4 is also divisible by 2, so it is an even number
∴ any odd integer is of the form 4q + 1 or, 4q + 3.
Answer:
Let a be any odd positive integer and b = 4. By division lemma there exist integer q and r such that
a = 4 q + r, where 0 ≤ r ≤ 4
so a = 4q or, a = 4q + 1 or, a = 4q + 2 or, a = 4q + 3
4q + 1 → 4 is divisible by 2 but 1 is not divisible by 2, so it is an odd number
4q + 2 → 4 is divisible by 2 and 2 is also divisible by 2, so it is an even number
4q + 3 → 4 is divisible by 2 but 3 is not divisible by 2, so it is an odd number
4q + 4 → 4 is divisible by 2 and 4 is also divisible by 2, so it is an even number
∴ any odd integer is of the form 4q + 1 or, 4q + 3.