Evaluate
6-2\sqrt{5}\approx 1.527864045
Expand
6-2\sqrt{5}
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\left(\sqrt{5}\right)^{2}-2\sqrt{5}+1
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{5}-1\right)^{2}.
5-2\sqrt{5}+1
The square of \sqrt{5} is 5.
6-2\sqrt{5}
Add 5 and 1 to get 6.
\left(\sqrt{5}\right)^{2}-2\sqrt{5}+1
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{5}-1\right)^{2}.
5-2\sqrt{5}+1
The square of \sqrt{5} is 5.
6-2\sqrt{5}
Add 5 and 1 to get 6.
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