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\(\sqrt{4\sqrt{2}-\sqrt{4+16\sqrt{6-4\sqrt{2}}}}+\sqrt{\sqrt{3}+\sqrt{228+50\sqrt{67-16\sqrt{3}}}}\)
\(\sqrt{4\sqrt{2}-\sqrt{4+16\sqrt{6-4\sqrt{2}}}}+\sqrt{\sqrt{3}+\sqrt{228+50\sqrt{67-16\sqrt{3}}}}\)
\(=\sqrt{4\sqrt{2}-\sqrt{4+16\sqrt{\left(\sqrt{2}-2\right)^2}}}+\sqrt{\sqrt{3}+\sqrt{228+50\sqrt{\left(\sqrt{3}-8\right)^2}}}\)
\(=\sqrt{4\sqrt{2}-\sqrt{4+16\left(2-\sqrt{2}\right)}}+\sqrt{\sqrt{3}+\sqrt{228+50\left(8-\sqrt{3}\right)}}\)
\(=\sqrt{4\sqrt{2}-\sqrt{36-16\sqrt{2}}}+\sqrt{\sqrt{3}+\sqrt{628-50\sqrt{3}}}\)
\(=\sqrt{4\sqrt{2}-\sqrt{\left(4\sqrt{2}-2\right)^2}}+\sqrt{\sqrt{3}+\sqrt{\left(\sqrt{3}-25\right)^2}}\)
\(=\sqrt{4\sqrt{2}-4\sqrt{2}+2}+\sqrt{\sqrt{3}+25-\sqrt{3}}\)
\(=\sqrt{2}+5\)
\(\sqrt{4\sqrt{2}-\sqrt{4+16\sqrt{6-4\sqrt{2}}}}+\sqrt{\sqrt{3}+\sqrt{228+50\sqrt{67-16\sqrt{3}}}}=\sqrt{4\sqrt{2}-\sqrt{4+16\sqrt{\left(2-\sqrt{2}\right)^2}}}+\sqrt{\sqrt{3}+\sqrt{228+50\sqrt{\left(8-\sqrt{3}\right)^2}}}=\sqrt{4\sqrt{2}-\sqrt{4+32-16\sqrt{2}}}+\sqrt{\sqrt{3}+\sqrt{228+400-50\sqrt{3}}}=\sqrt{4\sqrt{2}-\sqrt{36-16\sqrt{2}}}+\sqrt{\sqrt{3}+\sqrt{628-50\sqrt{3}}}=\sqrt{4\sqrt{2}-4\sqrt{2}+2}+\sqrt{\sqrt{3}+25-\sqrt{3}}=\sqrt{2}+\sqrt{25}=5+\sqrt{2}\)
\(A=\sqrt{24+16\sqrt{2}}-\sqrt{24-16\sqrt{2}}=\sqrt{\left(4+\sqrt{8}\right)^2}-\sqrt{\left(4-\sqrt{8}\right)^2}=\left|4+\sqrt{8}\right|-\left|4-\sqrt{8}\right|=4+\sqrt{8}-4+\sqrt{8}=4\sqrt{2}\)
tính x=\(\sqrt{97-56\sqrt{3}}+\sqrt{52+16\sqrt{3}}\)
y=\(\sqrt{33+20\sqrt{2}}+\sqrt{24-16\sqrt{2}}\)
Ta có: \(x=\sqrt{97-56\sqrt{3}}+\sqrt{52+16\sqrt{3}}\)
\(=\sqrt{49-2\cdot7\cdot4\sqrt{3}+48}+\sqrt{48+2\cdot4\sqrt{3}\cdot2+4}\)
\(=\sqrt{\left(7-4\sqrt{3}\right)^2}+\sqrt{\left(4\sqrt{3}+2\right)^2}\)
\(=\left|7-4\sqrt{3}\right|+\left|4\sqrt{3}+2\right|\)
\(=7-4\sqrt{3}+4\sqrt{3}+2\)
\(=9\)
Làm luôn phần y :D
y = \(\sqrt{33+20\sqrt{2}}+\sqrt{24-16\sqrt{2}}\)
y = \(\sqrt{33+2.10\sqrt{2}}+\sqrt{24-2.8\sqrt{2}}\)
y = \(\sqrt{33+2.5.2\sqrt{2}}+\sqrt{24-2.4.2\sqrt{2}}\)
y = \(\sqrt{25+2.5.\sqrt{8}+8}+\sqrt{16-2.4.\sqrt{8}+8}\)
y = \(\sqrt{\left(5+\sqrt{8}\right)^2}+\sqrt{\left(4-\sqrt{8}\right)^2}\)
y = |5 + \(\sqrt{8}\)| + |4 - \(\sqrt{8}\)|
y = 5 + \(\sqrt{8}\) + 4 - \(\sqrt{8}\) (Vì 4 > \(\sqrt{8}\) nên 4 - \(\sqrt{8}\) > 0)
y = 9
Vậy y = 9
Chúc bn học tốt!
mk chỉ lm đk với đề như này th à
\(\sqrt{28-16\sqrt{3}}-\sqrt{28+16\sqrt{3}}\)
Đặt A = \(\sqrt{28-16\sqrt{3}}-\sqrt{28+16\sqrt{3}}\)
nhận xét : A < 0, bình phương hai vế ta được :
\(A^2=\left(\sqrt{28-16\sqrt{3}}-\sqrt{28+16\sqrt{3}}\right)^2\)
\(\Rightarrow A^2=\left(\sqrt{28-16\sqrt{3}}\right)^2+\left(\sqrt{28+16\sqrt{3}}\right)^2-2\sqrt{\left(28-16\sqrt{3}\right)\left(28+16\sqrt{3}\right)}\)
=> \(A^2=28-16\sqrt{3}+28+16\sqrt{3}-2\sqrt{28^2-\left(16\sqrt{3}\right)^2}\)
=>\(A^2=56-2\sqrt{784-768}\)
=> \(A^2=56-2\sqrt{16}=56-2.4\)
=> \(A^2=48\)
=> \(A=\pm\sqrt{48}\) mà A < 0 nên
\(A=-\sqrt{48}\)
\(\sqrt{24+16\sqrt{2}}-\sqrt{24-16\sqrt{2}}=\sqrt{8\left(3+2\sqrt{2}\right)}-\sqrt{8\left(3-2\sqrt{2}\right)}\)
\(=\sqrt{8}.\left[\sqrt{\left(\sqrt{2}+1\right)^2}-\sqrt{\left(\sqrt{2}-1\right)^2}\right]=\sqrt{8}.\left(\sqrt{2}+1-\sqrt{2}+1\right)=2\sqrt{8}=4\sqrt{2}\)
\(\sqrt{24+16\sqrt{2}}-\sqrt{24-16\sqrt{2}}\)
\(=\sqrt{\left(4+2\sqrt{2}\right)^2}-\sqrt{\left(4-2\sqrt{2}\right)^2}\)
\(=4+2\sqrt{2}-4+2\sqrt{2}\)
\(=4\sqrt{2}\)
Giải:
\(\sqrt{24+16\sqrt{2}}-\sqrt{24-16\sqrt{2}}\)
\(=\sqrt{8+2.4.2\sqrt{2}+16}-\sqrt{16-2.4.2\sqrt{2}+8}\)
\(=\sqrt{\left(2\sqrt{2}+4\right)^2}-\sqrt{\left(4-2\sqrt{2}\right)^2}\)
\(=2\sqrt{2}+4-\left(4-2\sqrt{2}\right)\)
\(=2\sqrt{2}+4-4+2\sqrt{2}\)
\(=4\sqrt{2}\)
Vậy ...
Lời giải:
a. ĐKXĐ: $x\in\mathbb{R}$
PT $\Leftrightarrow \sqrt{(x-2)^2}=5$
$\Leftrightarrow |x-2|=5$
$\Leftrightarrow x-2=5$ hoặc $x-2=-5$
$\Leftrightarrow x=7$ hoặc $x=-3$ (đều tm)
b. ĐKXĐ: $x\geq -1$
PT $\Leftrightarrow \sqrt{16}.\sqrt{x+1}-3\sqrt{x+1}+\sqrt{4}.\sqrt{x+1}=16-\sqrt{x+1}$
$\Leftrightarrow 4\sqrt{x+1}-3\sqrt{x+1}+2\sqrt{x+1}=16-\sqrt{x+1}$
$\Leftrightarrow 4\sqrt{x+1}=16$
$\Leftrightarrow \sqrt{x+1}=4$
$\Leftrightarrow x+1=16$
$\Leftrightarrow x=15$ (tm)
\(\sqrt{16}=\sqrt{4^2}=4\)
\(\sqrt{16}=\sqrt{4^2=4}\)