Given that a,b,x and y are real numbers such that

a+b=23
ax+by=79
ax²+by²=217
ax³+by³=691

Determine ax⁴+by⁴

(In reply to this does it by xdog)

That is a great solution.  I figured there had to be a way of building it up recursively.

L(n) = L(n-1) + 6*L(n-2)

With the right hand totals chosen to keep it from being obvious.

Posted by Jer on 2013-10-08 09:45:05