【正文】
ethod of Solution Integrating Factor of Linear Firstorder Differential EquationAbstract: As for linear firstorder differential equation and it will not exist if it has only one unknown number of integrating factor. So the differential equation will be difficult to solve. This thesis gives three particular forms of integrating factors which proves the sufficient and necessary condition of existence. Keywords: Partial derivative, Partial differential equation, linear differential equation, integrating factor 7