HARMONY AND COORDINATION AMONG VARIOUS DEPARTMENTS OF A COMPANY CAN BE AN IMPORTANT FACTOR FOR OBTAINING COMPETITIVE ADVANTAGE. FOR MANY BUSINESSES, TRADE CREDIT REPRESENTS A MAIN SECTION OF COMPANY FINANCE AND IS USED AS ONE OF COORDINATION STRATEGIES IN A COMPANY. IN THIS STUDY, A NONLINEAR MODEL OF JOINT partial DELAYED PAYMENTS, PRICING, AND MARKETING STRATEGIES IS PRESENTED IN A SUPPLY CHAIN INCLUDING A RETAILER AND MULTIPLE CUSTOMERS. DEMAND RATE IS AN ENDOGENOUSVARIABLE AND DEPENDS ON MARKETING COST, SELLING PRICE AND THE LENGTH OF THE CREDIT PERIOD. TOOBTAIN BETTER INVENTORY MANAGEMENT, BOTH HOLDING AND ordering COSTS ARE CONTROLLABLE BY AN ADDED COST. THE PROPOSED PROBLEM IS FORMULATED IN TWO CASES FOR MAXIMIZING THE RETAILER’S PROFIT AND DETERMINES LENGTH OF THE CREDIT PERIOD, MARKETING COST, SELLING PRICE, HOLDING COST, ordering COST, PURCHASING COSTAND ORDER QUANTITY SIMULTANEOUSLY. EACH CASE IS MODELED A CONSTRAINED SIGNOMIAL GEOMETRIC PROGRAMMING WITH 2 DEGREES OF DIFFICULTY. FOR SOLVING OUR MODELS, WE TRANSFORM BOTH MODELS TO A REVERSED CONSTRAINT PROGRAMMING AND CAN OBTAIN THE OPTIMAL SOLUTIONS IN CLOSED FORMS FOR EACH CASE. THE APPLICABILITY OF THIS SOLUTION METHOD IS DEMONSTRATED BY A NUMERICAL EXAMPLE.