~-корень
a) 1/(~5+~~12+1) -- 1/(~5+~~12-1)= ~5+~~12-1/(5+~12 -1) -- ~5+~~12+1/ (5+~12-1)= *там сокращается ~5+~~12* 2 /(4+~12)= 8-2~12/(16-12)= 8-4~3/4= 2-~3
б) 1/ (1+~2) ++ 1/ (~2+~3)- ~3= 1-~2/(1-2) ++ ~2-~3/(4-9)-~3= ~2-1+(~3-~2)/5 -~3 =(5~2+~3-~2-5~3)/5 -1= 4 (~2-~3)/5 -1
в) [ 1/(~6+~5) +1/(~6-~5)]^2= [~6-~5/ (6-5) + ~6+~5/ 6-5]^2= [~ 6-~5+~6+~5 ] ^2= [2~ 6]^2= 4*6= 24