Then a (0 0,0,0), c (2 2,0,0), b (0 0,2,0), a1(0,2,2), b1(0 (0,4,2),
AA 1=(0，？ 2,? 2)，BC=B 1C 1=(2，2，？ 0).
So cos < aa 1, BC > = aa 1? BC|AA 1|？ | I've praised it all and stepped on it. What is your evaluation of 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 2018-03-28 (2011? As shown in the figure, in triangular prism ABC-a1b1c1,AB=AC=AA 1=3a, BC=2a, D is the midpoint of BC, E is the midpoint of AB, and F is C22012-60. In prism ABC-a1b1c1,AB=AC=AA 1=2, and ABC 1⊥ aa1c. In triangular prism ABC-a1b1c1,AC = BC = BB 1, and d is the midpoint of AB. The verification is: BC1/plane CA 16020 12-. The side is perpendicular to the bottom, with the angle ABC = 90, AB = BC = BB1= 2, M820 13-02- 16 as shown in the figure, in the triangular prism △ ABC-a1b1. ∠ bcc1= π/3372012-01as shown in the figure, the triangular prism ABC-a1b1c is known. And the side ABB 1A 1 is perpendicular to the bottom ABC92020-04- 17. As shown in the figure, the side lengths of regular triangular prism, ABC-A1B1C1are all A, and DE is the midpoint of CC 1 and AB respectively, A65438. As shown in the figure, in the triangular prism ABC-a1b1b, the side Aa 1b is a diamond, ∠ A 1AB = 60, AC=AB, and d is the midpoint of ab. 3 It's you. [{ ' URL ':'/d 0 1373 f 082025 AAF 5 1 1aa 256 e 9 edab 64034 f 1a 07？ 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 = 1720 1 1 12 10；