Question

prove that 7 into root 5 is irrational

Answer 1

Let 7,/ 5 is a rational no.

where 7,/5 = p/ q ; where both p and q both are co - prime

Now;

7,/5 = p/ q

,/5= p/ 7q

•°• Our assumption is wrong becoz irrational never = rational no.

So 7 ,/ 5 is an irrational no.

Answer 2

Use graphical method.

Using right angle. Take sides as 2,1,5 (pythagorean triples)

Theoretically multiplication of rational(7) and irrational(root 5) is always irrational.