Urgent! 20 15 years, the last question of the multiple-choice questions of mathematics and physics in Xiamen Senior Three Adaptability Examination 10, fill in the blanks 14. How to do it should be analyzed in detail. The problem 10 is equivalent to the integral of ∫[2n, (n+ 1)]( 1/x)dx. ∫[2n，(n+ 1)]( 1/x)dx = ln(2n)-ln(n+ 1)= 1

Ln[2n/(n+ 1)]. The limit is ln2, so C is chosen.

14, there is no exact way, but you can guess. Pass n as NE∑AM and cross CD as e. Then when e is the midpoint of CD.

λ+2μ is the minimum value. Its value is 8/3. That's what happens when you have nothing to do in the exam.