等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an
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等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an等差数列{an}的公差为2,
等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an
等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an
等差数列{an}的公差为2,前n项和sn=pn^2+2n,(n属于r),求p的值及an
Sn=pn^2+2n
Sn-1=p(n-1)^2+2(n-1)
则an=2pn-p+2
an-1=2p(n-1)-p+2
则d=2p=2 所以p=1
an=2n+1
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