发布网友 发布时间:2022-04-23 19:13
共4个回答
热心网友 时间:2023-10-14 10:31
梦梦
www.ogn189.com6Sn=an^2+3an+2
6S(n-1)=a(n-1)^2+3a(n-1)+2
6Sn-6S(n-1)=6an=an^2+3an+2-a(n-1)^2-3a(n-1)-2
6an=an^2+3an-a(n-1)^2-3a(n-1)
a(n-1)^2+3a(n-1)=an^2-3an
a(n-1)^2+3a(n-1)+9/4=an^2-3an+9/4
(a(n-1)+3/2)^2=(an-3/2)^2
热心网友 时间:2023-10-14 10:32
magnet:?xt=urn:btih:0af8dad0abf59d55add5683e440629b6aacc242f热心网友 时间:2023-10-14 10:32
请追问我并留下扣扣邮箱,热心网友 时间:2023-10-14 10:33
梦梦3d同人
www.ijx980.comsin ( α ± β ) = sinα · cosβ ± cosα · sinβ
sin ( α + β + γ ) = sinα · cosβ · cosγ + cosα · sinβ · cosγ + cosα · cosβ · sinγ - sinα · sinβ · sinγ
cos ( α ± β ) = cosα cosβ ? sinβ sinα
tan ( α ± β ) = ( tanα ± tanβ ) / ( 1 ? tanα tanβ )