In fact,the formula for calculating critical depth of duplex trapezoidal is to deal with a formula which has two parameters whose highest power is six,but in theory there is no answer.

• 梯形明渠临界水深实质上是求解含一个参数的一元六次方程,理论上无解析解,现已有简捷、准确、通用的直接计算方法;