Simplify the expression $\sqrt{6 - 2\sqrt{5}}$.

AlgebraRadicalsSimplificationSquare Roots
2025/7/12

1. Problem Description

Simplify the expression 625\sqrt{6 - 2\sqrt{5}}.

2. Solution Steps

We are looking for two numbers, aa and bb, such that
(ab)2=a2+b22ab=625(a-b)^2 = a^2 + b^2 - 2ab = 6 - 2\sqrt{5}.
Therefore, we need to find aa and bb such that a2+b2=6a^2 + b^2 = 6 and ab=5ab = \sqrt{5}.
We can deduce that a2b2=5a^2b^2 = 5. Let's assume a=5a = \sqrt{5} and b=1b = 1. Then
a2+b2=(5)2+12=5+1=6a^2 + b^2 = (\sqrt{5})^2 + 1^2 = 5 + 1 = 6.
So, we can write 625=(51)26 - 2\sqrt{5} = (\sqrt{5} - 1)^2.
Then we have:
625=(51)2=51\sqrt{6 - 2\sqrt{5}} = \sqrt{(\sqrt{5} - 1)^2} = |\sqrt{5} - 1|.
Since 5>1\sqrt{5} > 1, we have 51=51|\sqrt{5} - 1| = \sqrt{5} - 1.

3. Final Answer

51\sqrt{5} - 1