已经二次函数f(x)-1/2x2+2/3x 数列an的前n项和Sn ,点(n,Sn)在 y=f(x)图像上 求an的通项,我做到了 Sn=-1/2n2+2/3x当n=1时,a1=S1当n大于等于2时,an=Sn-Sn-1 an=Sn-Sn-1 这一步怎么化简
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/08 21:43:14
![已经二次函数f(x)-1/2x2+2/3x 数列an的前n项和Sn ,点(n,Sn)在 y=f(x)图像上 求an的通项,我做到了 Sn=-1/2n2+2/3x当n=1时,a1=S1当n大于等于2时,an=Sn-Sn-1 an=Sn-Sn-1 这一步怎么化简](/uploads/image/z/1159657-25-7.jpg?t=%E5%B7%B2%E7%BB%8F%E4%BA%8C%E6%AC%A1%E5%87%BD%E6%95%B0f%28x%29-1%2F2x2%2B2%2F3x+%E6%95%B0%E5%88%97an%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8CSn+%2C%E7%82%B9%EF%BC%88n%2CSn%EF%BC%89%E5%9C%A8+y%3Df%28x%29%E5%9B%BE%E5%83%8F%E4%B8%8A+%E6%B1%82an%E7%9A%84%E9%80%9A%E9%A1%B9%2C%E6%88%91%E5%81%9A%E5%88%B0%E4%BA%86+Sn%3D-1%2F2n2%2B2%2F3x%E5%BD%93n%3D1%E6%97%B6%2Ca1%3DS1%E5%BD%93n%E5%A4%A7%E4%BA%8E%E7%AD%89%E4%BA%8E2%E6%97%B6%2Can%3DSn-Sn-1+an%3DSn-Sn-1+%E8%BF%99%E4%B8%80%E6%AD%A5%E6%80%8E%E4%B9%88%E5%8C%96%E7%AE%80)
xRJ@,+4̤Nbqf`(VTjEEMAхum}L&ѕIZcwn=99smZeOm>8nHy.jn˷Pac4Mura-S=ڎ?ز{wa*xjka1ILӾ8ܥ9VvoFR&