积分变量 meaning in English

integration variable

For some integrators , the variable of integration may be other than time
对某些积分器而言，积分变量可以不是时间。
Where is called the integral sign , is called the integrand , and is the integral variable
其中被称为积分号，称为被积函数，被称为被积表达式，称为积分变量。
But in the course of calculation , we must change the parameter to another so that our deduction can answer the continuum of the parameter
但是在求解的过程中，由于变量代换和积分变量本身的连续性要求，使所得的结果只在一定条件下适用。