我有几个数学题不过是英文的..我想知道过程还有方法
1)Thesequence9,18,27,36,45,45,63.consistsofsuccessivemultiplesof9.Thissquenceisthenalteredbymultiplyingeveryothertermby-1,startingwiththefirstterm,toproducethenewsequence-9,18,-27,36,-45,54...ifthesumoffirstntermsofthisnowsequenceis180,determinen.
2)howmanyfive-digitpositiveintegershavethepropertythattheproductoftheirdigitis2000
3)Inthediagram,triangleABCisequilateralandtheradiusofitsinscribedcircleis1.AlargercicrcleisdrawnthroughtheverticesoftherectangleABCDE.whatisthediameterofthelargercircle.