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## test for your logic

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Krisi
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### Re: test for your logic

Xkalibur wrote:
krisi wrote:Xkalibur,
Do you want a numerical value to prove it?

No, there's no need for it. I'll show you how to do that in a logical way.

Answer.

A- is a rational number.
B- is an irrational number.
==============
A+B or A-B

1. Let's presume that sum A+B is a rational number:

A+B=C

C-> rational

2. If so, then B:

B=C-A would have been also rational as the difference of two rational numbers, but isn't so because it contradicts to the statement (B- an irrational number). Thus, our presumption was false and therefore sum A+B is an irrational number.

(A-B is similar to the above.)

Simple, isn't it?

Yes, yes. Got it!
Thanks.
esl member since 2007

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