问题
填空题
设数列{an}、{bn}都是等差数列,且a1=25,b1=75,a2+b2=100,那么由an+bn所组成的数列的第37项值为 .
答案
100
∵{an}、{bn}为等差数列,∴{an+bn}也为等差数列,设cn=an+bn,则c1=a1+b1=100,而c2=a2+b2=100,故d=c2-c1=0,∴c37=100.
设数列{an}、{bn}都是等差数列,且a1=25,b1=75,a2+b2=100,那么由an+bn所组成的数列的第37项值为 .
100
∵{an}、{bn}为等差数列,∴{an+bn}也为等差数列,设cn=an+bn,则c1=a1+b1=100,而c2=a2+b2=100,故d=c2-c1=0,∴c37=100.