Brandy Melville Sweater Womens Tan Knit Long Raglan Sleeve Crew Neck Pullover $25 Brandy Melville green knit sweater larger size $18 Brandy Melville Brianna Cotton Thick Stripe Sweater Beige & Cream One Size $30 Brandy Melville Green Brianna Cotton Crewneck Sweater Relaxed Oversi...
所以tann*tan(n+1)=(tan(n+1)-tann)/tan1 -1Sn=b1……+bn=tan1*tan2+tan2*tan3……+tann*tan(n+1)=(tan2-tan1)/tan1-1+(tan3-tan2)/tan1-1……+(tan(n+1)-tann)/tan1-1=(tan2-tan1+tan3-tan2……+tan(n+1)-tann)/tan1 -n=(tan(n+1)-tan1)/tan1 -n=tan(n+1)...
【解析】由已知可得an=n,则bn=tanntan (n+1)由tan1=tan[(n+1)-n]=tan(n+ly-tann 1+ tan(n+ltann 可得bn=tann·tan(n+1)=[tan(n+1)-tann]-1所以Sn=b1+b2+..+bntan [ tan2-tan1)+(tan3-tan2)+.+tan (n+)-tann]-n = (n+)-tanl]-n = tann+-I-n tan1 故答案为:tann+...
Stop Drop and Roll...Top - Tan Regular price$231.00 USDSold out Doctor Jones - Black Regular price$242.00 USD Testimonials Solid year of adventures with my favourite @bnvvt partner in crime. Best travel companion! @petspetra I've used it every day pretty much since I got it. still...
n1n1 2n21nn(Ⅱ)由题意和(Ⅰ)中计算结果,知bntan(n2)tan(n3),n1.另一方面,利用tan1tan((k1)k)tan(
解:(1)∵抛物线y=x2+bx+c过点C(0,2). ∴x=2 又∵tan∠OAC==2, ∴OA=1,即A(1,0). 又∵点A在抛物线y=x2+bx+2上. ∴0=12+b×1+2,b=-3 ∴抛物线对应的二次函数的解析式为y=x2-3x+2 (2)存在 过点C作对称轴l的垂线,垂足为D,如图所示, ∴x=-.∴AE=OE-OA=-1=,∵∠APC=90°...
【解析】试题分析:在正方形ABCD中,AB=CD.由M、N两点关于对角线AC对称,所以DM=BN=1, 再由题意可知tan∠AND===tan(90°-∠CDN),进而求出CN=BC-BN=4-1=3.再由题意可知tan∠AND=tan(90°-∠CDN)===. 试题答案 在线课程 练习册系列答案
【题目】如图,矩形ABCD中,E为边AB上一点,将△ADE沿DE折叠,使点A的对应点F恰好落在边BC上,连接AF交DE于点N,连接BN.若 BF⋅DF=15 ,tan∠N
BN_TAN创建的收藏夹BN_TAN内容:用这把三十几块的琴练习练习 young for you 口琴,如果您对当前收藏夹内容感兴趣点击“收藏”可转入个人收藏夹方便浏览
【解答】证明:∵tan(A-B)= tanA-tanB 1+tanA•tanB,∴tanA•tanB= tanA-tanB tan(A-B)-1,又∵数列{an}的通项公式an=tann•tan(n-1),∴an= tann-tan(n-1) tan[n-(n-1)]-1= tann-tan(n-1) tan1-1,∴Sn= 1 tan1[tan1-tan0+tan2-tan1+tan3-tan2+…+tann-tan(n-1)]-n=...