Question

if X equal to one by 4 minus root 5 and Y equal to 1 by 4 + root 5 then value of x cube + y cube is

Answer 1

= (1/4 - root 5)*3 + 3(1/4 -root 5) *2 (1/4+ root 5)+3(1/4 -root 5)(1/4 +root 5)*2+(1/4+root 5)*3

=1/64 - 5 root 5  +15/64+ root 5+ 15/64 - root 5  +1/64 - 5 root 5

=so, root 5 and - root 5 gets cancel and 5 root 5 and - 5 root 5

= 1/64 +15/64+15/64+1/64

= 32/64

=1/2