若x+y+z=2,x^2+y^2+z^2=2,1/x+1/y+1/z=1/3则 x^3+y^3+z^3=

题目

若x+y+z=2,x^2+y^2+z^2=2,1/x+1/y+1/z=1/3则 x^3+y^3+z^3=
设a.b为实数,规定运算a*b=(a+1)(1-b),a满足等式(a*a)*(a+1)=(a+1)*(a*a)则a的值为
再帮个忙:
1.
1÷(3+√3)+1÷(5√3+3√5)+1÷(7√5+5√7).......+1÷(49√47+47√49)=_____
2.
1÷(2√1+1√2)+1÷(3√2+2√3)+....1÷(100√99+99√100)=_____

答案

第一题：已知x+y+z=2,x^2+y^2+z^2=2,xy+yz+xz=3xyz;那么(x+y+z)^2=x^2+y^2+z^2+2(xy+yz+xz)=4; (x+y+z)^3=3(x+y+z)(x^2+y^2+z^2)-2(x^3+y^3+z^3)+6xyz=8;把已知量代进去即可求得x^3+y^3+z^3=3.第二题：对(a*a)*(a...