Say whether the following are true or false, backing up with examples, if is rational, and is irrational:

is irrational

is irrational

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- Jun 13th 2011, 08:09 AMTeaWithoutMussoliniIrrational numbers
Say whether the following are true or false, backing up with examples, if is rational, and is irrational:

is irrational

is irrational - Jun 13th 2011, 08:18 AMPlato
With having fifty postings, you should understand that this is not a homework service nor is it a tutorial service. Please either post some of your own work on these problems or explain what you do not understand about the question.

- Jun 13th 2011, 08:49 AMTeaWithoutMussolini
Sorry dude but I am posting the aspects of the course I am having trouble with before the exam (tomorrow).

These are exam questions from the Further discrete maths exam past papers.

The question is I dont know how to work out the answer?

You have to show whether or not they are irrational.

i know rational means it can be expressed as m/n, both integers. I think both are true that both are irrational? but I dont know how to prove it?

I had a little think about the first one using my brain and I think its a proof by contradiction, by writing m/n + b = p/q, so b= p/q - m/n = pn - mq/qn which is rational so if a + b is rational b is rational too. but the product i am not too sure? - Jun 13th 2011, 11:27 AMAlso sprach ZarathustraRe: Irrational numbers
- Jun 13th 2011, 12:03 PMemakarovRe: Irrational numbers
- Jun 15th 2011, 12:09 PMAmerRe: Irrational numbers
suppose that a+b rational

thats mean a+b = n/m

so b = n/m - a and you that the rational numbers is closed under addition so b is rational contradiction

the other is same