Prove that is irrational.


Now, let us assume that 2√7 / 7 is a rational number


2√7/7 = p/q (where, p & q are integers, q not equal to 0)


2√7 = 7p/q


√7 = 7p/2q


Here, LHS is an irrational number whereas RHS is a rational number.


So by contradiction 2√7 / 7 is an irrational number


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