Question

Prove that√2 is an irrational number​

Answer 1

Let's suppose √2 is a rational number. Then we can write it √2 = a/b where a, b are whole numbers, b not zero. We additionally assume that this a/b is simplified to lowest terms, since that can obviously be done with any fraction.

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A proof that the square root of 2 is irrational.

2 = (2k)2/b2

b2 = 2k2

2 more rows...

the mean of 100 observatios is 50. if one of the observation which was 50 is replaced 150 then what will be the resulting mean

Answer 2

If we substitute a = 2k into the original equation 2 = a2/b2, this is what we get:

2 = (2k)2/b2

2 = 4k2/b2

2*b2 = 4k2

b2 = 2k2

This means that b2 is even, from which follows again that b itself is even. And that is a contradiction!!!