Prove that is irrational.
⇒ a2 is divisible by 2
⇒ a is divisible by 2
Let a = 2c for some integer c.
Putting a = 2c in (i), we get
2 b2 = (2c)2
⇒ 2b2 = 4c2
⇒ b2 — 2c2
⇒ b2 is divisible by 2
⇒ b is divisible by 2.
Thus, 2 is a common factor of a and b. But, this contradicts the fact that ‘a’ and ‘b’ have no common factor other than 1.
The contradiction arises by assuming that is rational.
Hence, is irrational.
Find the largest number that will divide 398,436 and 542 leaving remainders 7, 11 and 15 respectively. Problems Based on Fundamental Theorem of Arithmetic