题目内容：

试判定4的m次方+4的n次方-4的二分之m+n+1值的符号.

优质解答

4^m+4^n-4^(m+n+1)/2
=(4^m/2)^2+(4^n/2)^2-2*(4^m/2)(4^n/2)
=(4^m/2-4^n/2)^2≥0
当m≠n
4^m+4^n-4^(m+n+1)/2>0