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#1 Re: Help Me ! » Real Analysis Help » 2009-06-23 12:57:34
to prove that is irrational,
let x = √2 +√3
square both sides,
x² = 2 + + 3
x² - 5 = 2√6
square again both sides,
x^4 - 10x² + 1 = 0
by the rational root theorem any rational root of this polynomial is either 1 or -1. +- 1, contradiction
thanks avon for the correction!
#2 Re: Help Me ! » help with real analysis » 2009-06-22 12:55:50
i get it now..thank you so much bobbym 
#3 Re: Help Me ! » help with real analysis » 2009-06-21 20:11:04
how did jane arrived at
?#4 Help Me ! » help with real analysis » 2009-06-21 15:40:09
- jay17
- Replies: 4
i really need help with this pls..thanks
1. Prove: If a is irrational, 1/a is irrational.
2. Prove that √2 + √3 is irrational.
3. Prove that if a is irrational, √a is irrational.
4. Prove: log 2 is irrational.
5. Prove: If cos2θ is irrational, cosθ is irrational.
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