WHAT IS MARGINAL COSTING AND STEPS IN IT?

MARGINAL COST DISTINGUISH BETWEEN FIXED COST AND VARIABLE COST.
  THE MARGINAL COST OF A PRODUCT IS TAKEN AS ITS VARIABLE COST ie COST OF LABOUR , MATERIAL COST...
   IF TOTAL OUPUT INCREASES ,THE TOTAL COST PER UNIT DECREASES.
   IN MANUFACTURING UNIT MARGINAL COSTING IS USED TO KNOW  THE BREAK POINT ie MINIMUM NUMBER OF UNITS REQUIRED TO MANUFACTURE INITIALLY FOR GENERATING PROFITS.......
1.RECOGNIZE
2.IDENTIFY
3.GATHER
4.SELECT THE BEST METHOD WHICH HAS MORE PROFITS.