∴sin2α=2sinαcosα=2425,cos2α=2cos2α- 1=-725, 1+sin2α 1+cos2α= 1+2425 1+(？ 725)=49 18.
(2) From the meaning of the question, |OC|=|OB|= 1, ∠COB=α+π3, from the cosine theorem.
| BC | 2 = | OC | 2+| OB | 2-2 | OB | | OC | cos∠COB = 1+ 1-2 cos(α+π3)= 2-2 cos(α+π3)。
∵α∈(0,π2),∴α+π3∈(π3,5π6),∴cos(α+π3)∈(-32, 12)，
∴|BC|2∈( 1,2+3)，
∴| BC |∈ (1, 6+ has been praised and stepped on. What's your comment on this answer? Comments: If your problem has not been solved, please describe your problem in detail and conduct free professional consultation through Baidu Legal Pro. Other similar questions 2018-02-12 (2014? Lubei district's second model) as shown in the figure, the coordinates of point A and point B are known as (2,0) and (0,4) respectively, and p is a point on the △AOB circumscribed circle ⊙C, 3820 1 1-07-29. (Shanghai) As shown in Figure 7, in the plane rectangular coordinate system, m(-2) if circle B passes through m (-2,0) and is tangent to circle A, find point B172014-09-21(201/kloc. As shown in the figure, let p be the intersection of the unit circle and the positive semi-axis of the X axis, m and n be the two points on the unit circle, and o be the coordinate origin, ∠ POM = 22016-03-10 (2014? As shown in the figure, in the rectangular coordinate plane xOy, O is the origin, points A and C are on the positive semi-axis of the X axis and Y axis respectively, and the four sides are 32016-12-01(2010? As shown in the figure, there are points A (6 6,0), B (0 0,8) and C (-4,0) on the rectangular coordinate plane, and points M and N are line segments AC720 13-0 1-04 respectively. As shown in the figure, point A is a point on the X axis, which is within △OAB. As shown in the figure, the starting edge OA of angle θ falls on the X axis, and its starting edge and ending edge intersect with the unit circle at point A and point C respectively (0 < θ < π 2). More similar questions? & gt recommended for you: F.context('cmsRight', [{'URL':'/d01373f082025aaf511aa256e9edab64034f1a07? 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 ':' '，}])； The price of electric cars has dropped many times. Is the quality guaranteed? What impact will the "network toilet" have? Is Huaqiang North's second-hand mobile phone reliable? Why is the cost of cancer treatment getting higher and higher? 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 = 1720047084；