Salut,
[tex]N^2=\left(\sqrt{8-\sqrt{15}}-\sqrt{8+\sqrt{15}}\right)^2=\\\\=\left(\sqrt{8-\sqrt{15}}\right)^2-2\cdot \sqrt{8-\sqrt{15}}\cdot \sqrt{8+\sqrt{15}}+\left(\sqrt{8+\sqrt{15}}\right)^2=\\\\=8-\sqrt{15}-2\sqrt{8^2-(\sqrt{15})^2}+8+\sqrt{15}=16-2\sqrt{49}=16-14=2,\\\\ceea\ ce\ trebuia\ demonstrat.[/tex]
Simplu, nu ?
Green eyes.
