`sqrt{1-4a+4a^2}-2a`
`=sqrt{(1-2a)^2}-2a`
`=|1-2a|-2a`
`TH1: a <= 1/2`
`=>1-2a >= 0`
`=> |1-2a|=1-2a`
Ta có:
`|1-2a|-2a=1-2a-2a=1-4a`
`TH2:a > 1/2`
`=> 1-2a<0`
`=>|1-2a|=-(1-2a)=2a-1`
Ta có:
`|1-2a|-2a=2a-1-2a=-1`
\(\sqrt{1-4a+4a^2}-2a\)
\(=\sqrt{\left(1-2a\right)^2}-2a\)
\(=\left|1-2a\right|-2a\)
`@` Với \(a\le\dfrac{1}{2}\) \(\Rightarrow\left|1-2a\right|-2a=1-2a-2a=1-4a\)
`@`Với \(a>\dfrac{1}{2}\) \(\Rightarrow\left|1-2a\right|-2a=2a-1-2a=-1\)
\(=\sqrt{\left(1-2a\right)^2}-2a=\left|1-2a\right|-2a\\ TH1:a\le\dfrac{1}{2}\\ \Rightarrow\left|1-2a\right|-2a=1-2a-2a=1-4a\\ TH2:a>\dfrac{1}{2}\\ \Rightarrow\left|1-2a\right|-2a=2a-1-2a=-1\)
