∵⊙Pn and ⊙Pn+ 1 are tangent to each other,
∴|PnPn+ 1|=rn+rn+ 1
∴(xn？ xn+ 1)2+(yn？ yn+ 1)2=yn+yn+ 1，
Square on both sides, arranged (xn? xn+ 1)2=4x2nx2n+ 1
Xn > xn+ 1 > 0，
∴xn-xn+ 1=2xnxn+ 1，
∴ 1xn+ 1？ 1xn=2
∴{ 1xn} arithmetic progression, the first term is L, and the tolerance is 2.
∴ 1xn= 1+(n？ 1)? 2=2n？ 1
∴xn= 12n？ 1,
∴rn= 1(2n？ 1)2(n∈N*)
(2) the total construction cost of the first n circular paths is t n.
∫Sn =πr2n =πx4n =π(2n？ 1)4
∴TN = 10(πs 1+ has been praised. What's your comment on this answer? Put away comments//high quality or satisfaction or special types or recommended answers dottimewindow.iperformance & window.iperformance.mark ('c _ best',+newdate); Recommend lawyer service: If your problem has not been solved, please describe your problem in detail. Through free professional consultation on Baidu Legal Pro and other similar issues, 2022- 12-09 points out the favorable conditions for the construction of Changsha-Zhuzhou-Xiangtan metropolitan area from the perspective of regional differences and connections. 20 17-05-30 analyzes the favorable conditions for the economic integration of Changsha-Zhuzhou-Xiangtan from the geographical perspective. Urban agglomeration is an experimental area for the reform of "two-oriented society" and a regional consortium promoted by the state. At the end of last year, the "Changsha-Zhuzhou-Xiangtan" urban agglomeration was approved as a comprehensive reform pilot zone for building a resource-saving and environment-friendly society in China. The following practices are similar to those of 20 14-09-28 at the end of last year. The "Changsha-Zhuzhou-Xiangtan" urban agglomeration was approved as the experimental zone for comprehensive reform of building a resource-saving and environment-friendly society in China. The following practices are in line with the "Trinity Changsha-Zhuzhou-Xiangtan Economy" plan put forward by the Hunan provincial government to promote the economic development of Changsha-Zhuzhou-Xiangtan urban agglomeration and urban development in three steps. R "12014-10-05 Read the" Changsha-Zhuzhou-Xiangtan Comprehensive Reform Experimental Zone "and complete the following questions. (1) "Two-oriented society" refers to _ _ _ _ _. (.Recommended for you: F.context('cmsRight', [{'URL':'/d 01373f082025aaf511aa256e9edab64034f1a07) is especially recommended. x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId':'A24KA00562 '，}，{ ' URL ':/s？ word = % E6 % AC % A7 % E6 % B4 % B2 % E6 % 9D % AF & sa = searchpromo _ ozb _ zhidao _ tuijian '，' src ':'/3 BF 33 a 87 e 950352 AAF 5 df 4954 143 fbf2b 2 1 18 b6b？ x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId ':' '，}])； Is Huaqiang North's second-hand mobile phone reliable? Why is the cost of cancer treatment getting higher and higher? What impact will the "network toilet" have? The price of electric cars has dropped many times. Is the quality guaranteed? I recommend f.context ('recbrand', [{"img": "\/86D6277F9E2F07083523F69DFB 24B 899A901F20d? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto "，" url":"/hm.js？ 6859 ce 5a af 00 FB 00387 e 6434 E4 FCC 925 "； var s = document . getelementsbytagname(" script ")[0]； s.parentNode.insertBefore(hm，s)； })(); window . TT = 17 1970 1996；