观察下列等式:3^1=3,3^2=9,3^3=27,3^4=81,3^5=243,3^6=729,3^7=2187,…
问题描述:
观察下列等式:3^1=3,3^2=9,3^3=27,3^4=81,3^5=243,3^6=729,3^7=2187,…
3^1+3^2+3^3+3^4+…3^2013的末尾数字是?
答
3^1=3,
3^2=9,
3^3=27,
3^4=81,
3^5=243,
3^6=729,
3^7=2187
...
末位是按3,9,7,1循环的
2013÷4=503余1
∴3^2013的末位数字是3额,看清题目好么,我是说3^1+3^2+3^3+3^4+…3^2013的末位数字,不单单是3^20133末尾33*3末尾93*3*3末尾73*3*3*3末尾13*3*3*3*3末尾32013/4=503余1503*(3+9+7+1)+3=10060+3=10063所以末尾为3