bn 2=3log2分之1an

已知数列{log2(an-1)}为等差数列,且a1=3,a2=5可以得到该等差数列的公差d：d＝log2(a2-1)-log2(a1-1)＝log2(5-1)-log2(3-1)＝log2(4)-lo

∵a3,a10是方程2x^2-9x+1=0的两根∴a3×a10=1/2∵等比数列{an}∴a1×a12=a2×a11=a3×a10=……=1/2log2a1+log2a2+...+log2a12=1o

n2是什么再问：b乘以n的平方再答：根号7大于2小于3，所以m=2,n=3-根号7amn+bn2=-2(3-√7)a+(3--√7)^2b=6a+16b-2-√7(a+3b)=1ab为有理数,所以a+

没有错...换底公式的运用于逆运用.log(2)(3)xlog(3)(7)=ln3xln7/ln2xln3=ln7/ln2=log(2)(7)

an+1=3an-2an-1则a(n+1)-an=2(an-a(n-1))所以{a(n+1)-an}是以a2-a1=2是为首项,2为公比的等比数列所以a(n+1)-an=2*2^(n-1)=2^n而b

a4/a1=q³=8q=2∴an=2×2^(n-1)=2^n∴bn=1/{log2(2^n)×log2[2^(n+1)]}=1/[n(n+1)]∵bn=1/[n(n+1)]=1/n-1/(n

(1)log2（a1-1）-log2(a3-1)=-2dlog2(8)-log2(2)=2dd=1log2(an-1)=nan=2^n+1（n属于N*）(2)1/（an-a（n-1）)=1/(2^(n

log(2,9)=log(2,3^2)=2log(2,3)log(2,8)=log(2,2^3)=3log(2,2)=3所以(log2,9)/(log2,8)=2/3(log2,3)

已知数列{bn}={log2(an-1)}为等差数列,且a1=3a3=9→b1=log2(3-1)=log2(2)=1,b2=log2(9-1)=log2(8)=3,公差d=3-1=2,∴bn=1+(

证：b1=log2(a1+1)=log2(3+1)=log2(4)=2a(n+1)=an²+2ana(n+1)+1=an²+2an+1=(an+1)²b(n+1)=log

设数列log2(an-1)公差为dd=long2(an-1)-log2(a(n-1)-1)=log2[(an-1)/(a(n-1)-1]所以(an-1)/(a(n-1)-1)=2^d而由a1=3a2=

an=3n-1由an+1=an+3得知公差d=3所以an=a1+（n-1）d=3n-1

/>对数有意义,an>0log2(a(n+1))=1+log2(an)=log2(2an)a(n+1)=2an数列{an}是以2为公比的等比数列.a101+a102+a103+...+a200=(a1

答：1)f(x)=log1/2|sinx|,底数1/2,真数|sinx|>0所以：x≠kπ所以：定义域为x={x|x≠kπ,k∈Z}0

log2（a1）+log2（a2）+……+log2（a8）=log2(a1×a2×…×a8)∵等比数列∴a1a8=a2a7=a3a6=a4a5=32∴log2(a1×a2×…×a8)=log2(32^

(!)由题意可知log2(a1-1)+2d=log(a3-1)所以log2(2)+2d=log2(8)1+2d=3d=1故an=a1+(n-1)d=log2(2)+(n-1)*1=1+n-1=n(2)

log2(a1a2*……*a2009)=2009a1a2*……*a2009=2^2009a1a2009=a2a2008=……=a1004a1006=(a1005)²所以a1a2*……*a20

（I）设等差数列{log2（an-1）}的公差为d．由a1=3，a3=9得2（log22+d）=log22+log28，即d=1．所以log2（an-1）=1+（n-1）×1=n，即an=2n+1．（

y=log(1/2)(√(3x-2)求定义域的话：3x-2>0,x>2/3求值域的话：y∈R单调减区间（2/3,＋∞)

log2(x+3)+log2(x+2)=1log2{(x+3)*(x+2)}=1(x+3)*(x+2)=2x^2+5x+4=0(x+4)(x+1)=0所以x=-4或-1因为x+3>0x+2>0所以x>