\(\text{Rút gọn:}\)\(\text{Ví dụ:}\)\(\sqrt{9+4\sqrt{5}}-2\) 9+4 căn 5= căn 5 tất cả bình +2.căn 5 .2+ 5 4 9-5 2 bình=(căn 5+2 tất cả bình) \(=\sqrt{\left(\sqrt{5}\right)^2+2.\sqrt{5}.2+2^2}-2\)\(=\sqrt{\left(\sqrt{5}+2\right)^2}-2\)\(=|\sqrt{5}+2|-2=\sqrt{5}+2-2=\sqrt{5}\)\(\text{Tương tự vd, rút...
Đọc tiếp
\(\text{Rút gọn:}\)
\(\text{Ví dụ:}\)\(\sqrt{9+4\sqrt{5}}-2\)
\(=\sqrt{\left(\sqrt{5}\right)^2+2.\sqrt{5}.2+2^2}-2\)
\(=\sqrt{\left(\sqrt{5}+2\right)^2}-2\)
\(=|\sqrt{5}+2|-2=\sqrt{5}+2-2=\sqrt{5}\)
\(\text{Tương tự vd, rút gọn:}\)
\(1.\sqrt{5+2\sqrt{6}}-\sqrt{2}\)
\(2.\sqrt{7-2\sqrt{10}}+\sqrt{2}\)
\(3.\sqrt{8-2\sqrt{15}}+\sqrt{3}\)
