\(\dfrac{5-2\sqrt{5}}{2\sqrt{5}-2}.\dfrac{5+3\sqrt{5}}{3\sqrt{5}-2}\)
\(=\dfrac{\left(5-2\sqrt{5}\right)\left(5+3\sqrt{5}\right)}{\left(2\sqrt{5}-2\right)\left(3\sqrt{5}-2\right)}\)
\(=\dfrac{25+15\sqrt{5}-10\sqrt{5}-30}{30-4\sqrt{5}-6\sqrt{5}+4}\)
\(=\dfrac{-5+5\sqrt{5}}{34-10\sqrt{5}}\)
Tính
D= căn(4+căn(10+2căn5)) + căn(4-căn(10+2căn5))
a)(2căn8+3căn5-7căn2)(căn72-5căn20-2căn2) b)2căn8căn3-2căn5căn3-3căn20căn3 c)1/2+căn5+2căn2+căn10 d)3+4căn3/căn6+căn2-căn5
Cần gấp, m.n ơi giúp vs
X^2căn5 - 20 =0
2+√5/√2+√3+√5 +2-√5/√2-√3-√5
11) \(\dfrac{5+\sqrt{5}}{5-\sqrt{5}}\) + \(\dfrac{5-\sqrt{5}}{5+\sqrt{5}}\)
12) \(\dfrac{3+2\sqrt{3}}{\sqrt{3}}\) + \(\dfrac{2+\sqrt{2}}{\sqrt{2}+1}\) - \(\dfrac{1}{2-\sqrt{3}}\)
Tính (√5-2)/(2+2√5)-1/(2+2√5)-2/(2+√5)
\(\left(\sqrt{5+\sqrt{5}}+\sqrt{5-\sqrt{5}}-\sqrt{\frac{5}{2}+\sqrt{5}}\right)^2+\left(\sqrt{5+\sqrt{5}}-\sqrt{5-\sqrt{5}}-\sqrt{\frac{5}{2}-\sqrt{5}}\right)^2\)
Q=(5-2 căn 5/2-căn 5 trừ 2 riêng).(5+3 căn 5/3+ căn 5 trừ 2 riêng)
trục căn thức và thực hiện phép tính
1) \(\left(1-\dfrac{5+\sqrt{5}}{1+\sqrt{5}}\right)\left(\dfrac{5-\sqrt{5}}{1-\sqrt{5}}-1\right)\)
2) \(\left(\dfrac{5-2\sqrt{5}}{2-\sqrt{5}}-2\right)\left(\dfrac{5+3\sqrt{5}}{3+\sqrt{5}}-2\right)\)
