Briefly On the Solutions of Item Formula

From gradation the definitionan+1-an=d(dis constant) and etc.of the few rows compare the definition (an+1)/(an)=q(q≠0) of the few rows and can know,the gradation few rows and etc.Comparing few rows is the special situations that passes to push few rows for passing to push a form another,can consider according to the characteristics of the topic,will pass to push the few rows conversion the gradation few rows or etc.to compare few rows to solve.This text provides reference to some few methods that pass to push few rows in brief to beg an item formula to.