how to prove √(√2+√3) is irrational?
回答 (2)
Suppose to the contrary that x = √(√2+√3) were rational.
Squaring both sides:
x^2 = √2+√3.
Squaring both sides again:
x^4 = 5 + 2√6
==> √6 = (x^4 - 5)/2.
Since x is assumed rational, it follows via closure axioms of the set of rational numbers that (x^4 - 5)/2 is also rational.
This is a contradiction, because √6 is irrational (which can be proved in the same manner that √2 is irrational).
Therefore, √(√2+√3) is irrational.
I hope this helps!
Bc the answer would come out to be the sq root of 5 which is an odd number. And you can't have a odd number under a sq rt as the answer
收錄日期: 2021-05-03 15:24:52
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