Find the minimum of { (x + 1/x)6 - (x6 + 1/x6) - 2 }/{ (x + 1/x)3 + (x3 + 1/x3) }, for x > 0.
Solution
Easy
Simplifying, we find that the expression is 3(x + 1/x). This has minimum at x = 1, value 6.
© John Scholes
jscholes@kalva.demon.co.uk
12 Dec 1998