若A,B互为相反数,C,D互为倒数,
A+B=0CD=1
则根号a的立方加b的立方加根号cd
=根号(a^3+b^3) +根号cd
=根号(a+b)(a^2-ab+b^2) +根号1
=根号0*(a^2-ab+b^2) +1
=0+1
=1