(1/4)^7, 0,25 và [( 1/4)^2]^4

Lời giải:

 \({\left( {\frac{1}{4}} \right)^7}\,.\,0,25 = {\left( {\frac{1}{4}} \right)^7}\,.\,\frac{1}{4} = {\left( {\frac{1}{4}} \right)^{7 + 1}} = {\left( {\frac{1}{4}} \right)^8}\);

\({\left[ {{{\left( {\frac{1}{4}} \right)}^2}} \right]^4} = {\left( {\frac{1}{4}} \right)^{2\,.\,4}} = {\left( {\frac{1}{4}} \right)^8}\).

Vậy \({\left( {\frac{1}{4}} \right)^7}\,.\,0,25\) = \({\left[ {{{\left( {\frac{1}{4}} \right)}^2}} \right]^4}\).