Question

Rút gọn biểu thức :\(\sqrt{1-4a+4a^2}\)- 2a   (jup m)

Answer 1

\(A=\sqrt{1-4a+4a^2}-2a=\sqrt{\left(1-2a\right)^2}-2a=\left|1-2a\right|-2a\)

Nếu  \(a\le\frac{1}{2}\)thì:  \(A=1-2a-2a=1-4a\)

Nếu  \(a>\frac{1}{2}\)thì:  \(A=2a-1-2a=-1\)

Answer 2

ta có:\(\sqrt{\left(1-2a\right)^2}-2a=|1-2a|-2a\)

th1:neu 1-2a <0 <=>1<2a<=>1/2<a:

l1-2al=2a-1

=>2a-1-2a=-1

th2:neu 1-2a>=0=>1>=2a=>1/2>a ta co:

l1-2al=1-2a

=>1-2a-2a=1-4a