Given that sqrt(15) is an irrational number, prove that sqrt(3) + sqrt (5) is an irrational number. Please teach me how to solve this question. Thank you very much.
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Originally Posted by beta12 Given that sqrt(15) is an irrational number, prove that sqrt(3) + sqrt (5) is an irrational number. Please teach me how to solve this question. Thank you very much. Suppose sqrt(3)+sqrt(5) is rational, then: (sqrt(3)+sqrt(5))^2=3+2sqrt(15)+5=8+2sqrt(15) is rational, which implies that sqrt(15) is rational - a contradiction. Hence sqrt(3)+sqrt)5) is irrational. RonL
Hi Captainblack, Thank you very much.
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