((1/2)^2 + (1/4)^2)/(1/2 + 1/4)^2=
=(1/4 + 1/16)/(3/4)^2=
=5/16/(9/16)= 5/9
----------------------------------
(1/2 + 1/3)/(1/2/1/3)/((1/2)^2 - (1/3)^2)=
=5/6/(1/2/1/3)/((1/4) - (1/9))=
=5/6/(1/2/1/3)/(5/36)=
=5/(5/36)= 36
125)
1/4+1/16 = 5/16
(1/2+1/4)^2 = (3/4)^2 = 9/16
5/16*16/9 = 5/9
1/2+1/3 = 5/6
1/2-1/3 = 1/6
5/6*6 = 5
(1/4-1/9) = (9-4)/36 = 5/36
3*36/5 = 36
126)