1.把p点坐标代入直线,可得关于an和an+1的关系式:an+1-an=1,则数列an是等差数列,则an=n;
2.即bn=1/n(n+2)=1/2(1/n-1/n+2)(此处为裂项),则Tn=b1+b2+.+bn=1/2(1+1/2-1/n+1-1/n+2)(你在合并过程中会发现有很多项抵消)=3/4+(2n+3)/2(n+1)(n+2)
1.把p点坐标代入直线,可得关于an和an+1的关系式:an+1-an=1,则数列an是等差数列,则an=n;
2.即bn=1/n(n+2)=1/2(1/n-1/n+2)(此处为裂项),则Tn=b1+b2+.+bn=1/2(1+1/2-1/n+1-1/n+2)(你在合并过程中会发现有很多项抵消)=3/4+(2n+3)/2(n+1)(n+2)