补偿电容的作用是什么？
参考答案：
补偿电容是为了补偿因轨道电路过长，钢轨电感的感抗所产生的无功功率损耗，改善轨道电路在钢轨上的传输性能。
已知数列{an}的前n项和是sn=2n2+3n+3，则数列的通项an=______．
To everyone's surprise, the difficult question was answered by a five-year-old boy in the end. [ ]
A. publicly
B. orderly
C. swiftly
D. correctly
