( x + 1/2)^4

Lời giải:

\({\left( {x + \frac{1}{2}} \right)^4}\)\( = {x^4} + 4.{x^3}.\frac{1}{2} + 6.{x^2}.{\left( {\frac{1}{2}} \right)^2} + 4.x.{\left( {\frac{1}{2}} \right)^3} + {\left( {\frac{1}{2}} \right)^4}\)

\( = {x^4} + 2{x^3} + \frac{3}{2}{x^2} + \frac{1}{2}x + \frac{1}{{16}}\).