a)
[3/(2√3-√5)-1/(√5-√3)-2/(3√3+2√5)] :(√5-√3)=
=[3(2√3+√5)/(12-5)-(√5+√3)/(5-3)-2(3√3-2√5)/(27-20)] ×1/(√5-√3)=
=[3(2√3+√5)/7-(√5+√3)/2-2(3√3-2√5)/7] ×(√5+√3)/2=
=[6√3+3√5-6√3+4√5)/7-(√5+√3)/2] ×(√5+√3)/2=
=[7√5/7-(√5+√3)/2] ×(√5+√3)/2=
=[√5-(√5+√3)/2] ×(√5+√3)/2=
=(2√5-√5-√3)/2 ×(√5+√3)/2=
=(√5-√3)/2 ×(√5+√3)/2=
=(5-3)/4=2/4=1/2=0,5
b)
(0,5+1/2)^2012+(0,5+1/2)^(-2011)=
=1^2012+1/1^2011=1+1=2
