Răspuns:
[tex]\frac{366080}{6789783}[/tex]
Explicație pas cu pas:
[tex]A=\frac{1}{2} *\frac{3}{4} *\frac{5}{6} *..*\frac{19}{20} = \frac{715}{3584} \\\\ B=\frac{2}{3} *\frac{4}{5} *\frac{6}{7}*..*\frac{20}{21} =\frac{262144}{969969} \\\\A*B=\frac{715}{3584} *\frac{262144}{969969} =\frac{366080}{6789783}[/tex]
Sper ca te-am ajutat! Bafta! :)
