方程（）是二阶微分方程 A、<img width="82" height="42" alt="" src="/lqwvjeImg/5f/5f077d95f7b6ef0deabf5359a3cac6e7.png" style="" /> B、<img width="104" height="47" alt="" src="/lqwvjeImg/a6/a67e19ef0872c7bd79d59039e5a328b0.png" style="" />； C、<img width="135" height="44" alt="" src="/lqwvjeImg/cf/cfd29a0befa7d735d1832223a2a02e55.png" style="" />； D、<img width="96" height="30" alt="" src="/lqwvjeImg/66/66f028c6fe51d84b3644175f08d7f79c.png" style="" />