Lời giải:
$(4+\sqrt{15})(\sqrt{10}-\sqrt{6})\sqrt{4-\sqrt{15}}$
$=(4+\sqrt{15})(\sqrt{5}-\sqrt{3})\sqrt{8-2\sqrt{15}}$
$=(4+\sqrt{15})(\sqrt{5}-\sqrt{3})\sqrt{(\sqrt{5}-\sqrt{3})^2}$
$=(4+\sqrt{15})(\sqrt{5}-\sqrt{3})(\sqrt{5}-\sqrt{3})$
$=(4+\sqrt{15})(8-2\sqrt{15})=2(4+\sqrt{15})(4-\sqrt{15})$
$=2(4^2-15)=2$ (đpcm)
B1:CHƯNG MINH ĐẲNG THỨC:
A)\(\sqrt{10}-\sqrt{6}=2\sqrt{4-\sqrt{15}}\)
B)\(\left(\sqrt{10}-\sqrt{6}\right)X\left(4+\sqrt{15}\right)X\sqrt{4-\sqrt{15}=2}\)
CM các đẳng thức sau:
\(\sqrt{3-\sqrt{5}}(3+\sqrt{5})\left(\sqrt{10}-\sqrt{2}\right)=8\)
\(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}=2}\)
chứng minh đẳng thức
a) \(\left(5+\sqrt{21}\right).\left(\sqrt{14}-\sqrt{6}\right).\left(\sqrt{5-\sqrt{21}}\right)=8\)
b) \(\left(\sqrt{6}+\sqrt{2}\right)\left(\sqrt{3}-2\right)\left(\sqrt{3}+2\right)=-2\)
c) \(\sqrt{4+\sqrt{15}}+\sqrt{4-\sqrt{15}}-2\sqrt{3-\sqrt{5}}=\sqrt{2}\)
ai nhanh mk tick cho nha !!!!
chứng minh đẳng thức:
\(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}=2\)
Thực hiện phép tính ( rút gọn biểu thức )
a) \(\left(\sqrt{14}+\sqrt{6}\right)\sqrt{5-\sqrt{21}}\)
b) \(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\)\(\sqrt{4-\sqrt{15}}\)
\(\left(\sqrt{6}+\sqrt{10}\right).\sqrt{4-\sqrt{15}}\)
\(\left(3+\sqrt{15}\right).\left(\sqrt{10}-2\right).\sqrt{3-\sqrt{5}}\)
\(\left(4+\sqrt{15}\right).\left(\sqrt{10}-\sqrt{6}\right).\sqrt{4-\sqrt{15}}\)
Chứng minh
\(\left(4+\sqrt{15}\right)\left(10-\sqrt{16}\right)\sqrt{4-\sqrt{15}}=2\)
B1: rút gọn biểu thức:
a, \(\frac{\left(4\sqrt{21}-4\sqrt{15}-\sqrt{4}+\sqrt{10}\right)}{4\sqrt{6}-2+4\sqrt{15}-\sqrt{10}}\)
b, \(\left(\sqrt{5}+\sqrt{3}\right)\sqrt{8-2\sqrt{15}}\)
c, \(\sqrt{3-\sqrt{5}}-\sqrt{3+\sqrt{5}}\)
d, \(\left(2-\sqrt{3}\right)\left(\sqrt{6}+\sqrt{2}\right)\sqrt{2+\sqrt{3}}\)
Chứng minh các đẳng thức sau:
e) \(\left(\dfrac{3}{2}.\sqrt{6}+2.\sqrt{\dfrac{2}{3}}-4.\sqrt{\dfrac{3}{2}}\right).\left(\dfrac{3}{2}.\sqrt{6}+2.\sqrt{\dfrac{2}{3}}+4.\sqrt{\dfrac{3}{2}}\right)=-\sqrt{2}\)
