prove that 3+√2 is irrational
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Step-by-step explanation:
Ok, so the proof goes like this:
We prove it by contradiction: any rational number can be written as the ratio of two integers p and q, which are coprime (this is the definition of a rational number)
So, suppose 2–√3 is rational:
2–√3=pq
but then
2=p3q3
p3=2q3
This therefore means that p3 is an even number (2n is an even number for all integer n) . From the properties of multiplication, we can then deduce that if p3 is even, p is even.
So we can rewrite p=2n, for some unknown, integer n.
Therefore (2n)3=2q3
8n3=2q3
q3=4n3
Now we repeat the even argument - show that q is also even (all multiples of 4 are even), and since p and q are both even, they are not coprime,...
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