用待定系数法求微分方程<img src="/lqwvjeImg/ae/ae972424e965cac6c34a7ceb508c86ba.png"style="width:124px;height:24px;">的一个特解时,应设特解的形式为<img src="/lqwvjeImg/f4/f483a614ecbd3455b860e48e9127ed40.png"style="width:19px;height:24px;">=( )<br>· <img src="/lqwvjeImg/57/5753139ba6135abbb939038fdb6cc075.png"style="width:40px;height:20px;">.<br>· <img src="/lqwvjeImg/ac/ac1089a14e645aafd5a976840082bda7.png"style="width:27px;height:20px;">.<br>· <img src="/lqwvjeImg/f8/f83e8556cbf35566627ba8a347a537e4.png"style="width:81px;height:24px;"><br>· <img src="/lqwvjeImg/5f/5f864a913b88824344dde0f24b99c718.png"style="width:40px;height:20px;">.