Đặt \(x=\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}>0\)
\(\Rightarrow x^2=8+2\sqrt{\left(4+\sqrt{10+2\sqrt{5}}\right)\left(4-\sqrt{10+2\sqrt{5}}\right)}\)
\(\Rightarrow x^2=8+2\sqrt{16-\left(10+2\sqrt{5}\right)}\)
\(\Rightarrow x^2=8+2\sqrt{6-2\sqrt{5}}\)
\(\Rightarrow x^2=8+2\sqrt{\left(\sqrt{5}-1\right)^2}\)
\(\Rightarrow x^2=6+2\sqrt{5}=\left(\sqrt{5}+1\right)^2\)
\(\Rightarrow x=\sqrt{5}+1\)