“The product of two consecutive positive integers is divisible by 2”. Is this statement true or false? Give reasons.
@genius12
2 consecutive positive integers means one integer must be even and the other must be odd all even numbers are divisible by 2 when you multiply the odd and even together, you can still divide out the 2 from the even number
False. 1*3 = 3 <- not even lol.
consecutive?
Ok..
True. There will be an even and odd, so of course their product will be divisible by 2.
Yes ok guys I think @goformit100 gets the idea here. we don't all need to crowd around the same question. move on to other questions.
Goformit, is it clear to you?
You can take cases here. Case 1 : a is even. a = 2q (using euclid's division algorithm, q is positive integer) \(\bf{\cfrac{a(a+1)}{2} = \cfrac{2q(a+1)}{2} = q(a+1)}\) , which is a positive integer. So, a(a+1) is divisible by 2. Case 2 : a + 1 is even \(\bf{\cfrac{a(a+1)}{2} = \cfrac{2q(a)}{2} = aq}\) which is also an integer So, a(a+1) is divisible by 2.
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