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Prove that 2 + 3 √ 5 is an irrational number, it is being given that √ 5
is an irrational number.?
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Prove that 2 + 3 √ 5 is an irrational number, it is being given that √...
Proof that 2 + 3√5 is an irrational number

Assumption:
Given that √5 is an irrational number.

Assume that 2 + 3√5 is a rational number

Definition of Rational Number:
A rational number is a number that can be expressed as a ratio of two integers.

Let's assume 2 + 3√5 is rational

Express 2 + 3√5 as a ratio of two integers:
Let 2 + 3√5 = a/b, where a and b are integers with no common factors.

Simplify the equation:
2 + 3√5 = a/b
3√5 = a/b - 2
3√5 = (a - 2b)/b

Square both sides:
(3√5)^2 = ((a - 2b)/b)^2
45 = (a^2 - 4ab + 4b^2)/b^2
45b^2 = a^2 - 4ab + 4b^2

Conclusion:
After squaring both sides, we have obtained a contradiction as the left-hand side is an integer (45b^2) while the right-hand side is not necessarily an integer. This implies that our assumption that 2 + 3√5 is a rational number is incorrect.

Therefore, 2 + 3√5 is an irrational number.
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Prove that 2 + 3 √ 5 is an irrational number, it is being given that √ 5is an irrational number.?
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