f*********s
发帖数: 34 | 1 One american high school student asked me a problem from the US high school
national math competition he took part in several days ago. He and I worked
on it several days and couldn't find the answer.
The problem is:
croot(croot(2)-1) = croot(a) + croot(b) + croot(c)
and a,b and c are rational numbers, find a+b+c=?
note: croot(x) means cubic root of x.
Anyone can solve the problem? Hope to see your answer and solutions. | r******t
发帖数: 2551 | 2 It's easy. Just let a = -b. You will get the answer right away.
The logic is: if there is a unique answer to this problem, then
any combination of (a,b,c) should lead you to the answer.
【在 f*********s 的大作中提到】
: One american high school student asked me a problem from the US high school
: national math competition he took part in several days ago. He and I worked
: on it several days and couldn't find the answer.
:
: The problem is:
:
: croot(croot(2)-1) = croot(a) + croot(b) + croot(c)
: and a,b and c are rational numbers, find a+b+c=?
:
: note: croot(x) means cubic root of x.
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