Find the general term and the sum ofn terms of the series -3,-1,11,39,89,167.
Find the general term and the sum ofn terms of the series -3,-1,11,39,89,167.
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Find the sum of n terms of the series whose nth term is 3(4n+4n²)-5n³.
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Resolve (1+52x+30x2-24x3)/(3x2-x-1)2 into partial fractions.
Factor the following expressions:x(y - z)³ + y(z -x)³ + z(x - y)³
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设{an}是首项为1的正项数列,且(n+1) - n+an+1an=0(n=1,2,3⋅⋅⋅),则它的通项公式是an=______.
设数列{an}的通项为an=2n-7(n∈N),则|a1|+|a2|+⋯+|a15|=______.
已知数列{an}满足a1=1,an+1=(1)记bn=a2n,写出b1,b2,并求数列{bn}的通项公式;(2)求{an}的前20项和.
设正数数列{an },{bn}满足:a1=b1=1,bn=an bn-1-1/4(n≥2).求4+1/(a1 a2⋯ak )的最小值,其中m是给定的正整数.
在各项均为正数,且满足下列条件的数列{an}中,a9可能的最大值和最小值分别为M和m,则M+m的值为【 】(1) a7=40(2)对于任意正整数n,an+2=