In △AA 1C, AC = 1, aa 1 = c 1c = 2, ∠ caa 1 = π 3,

A 1c2 = ac2+aa 12 from cosine theorem? 2AC？ aa 1 cos∠CAA 1 = 12+22？ 2× 1×2×cosπ3=3，

Therefore, a 1c = 3. Therefore, there are AC2+A 1C2=AA 12, so AC⊥A 1C, and AC∩BC=C, ∴A 1C⊥ plane ABC. ..

(2) As shown in the figure, take C as the origin of the spatial coordinate system, and the straight lines of CA, CA 1 and CB as the X, Y and Z axes respectively.

Then c (0 0,0,0), b (0 0,0, 1), a (1, 0), a1(0 (0,3,0),

From this, we can get: d (12,32,0), e (0 0,32,0) BD = (12), praised and trampled. 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); Lawyer recommendation service: If your problem has not been solved, please describe your problem in detail, and provide free professional consultation for other similar problems through Baidu Law Pro 20 13-07-063. As shown in the figure, in triangular prism ABC-a1b1c1,AA 1⊥ face ABC, AA 1=3, and d is the midpoint of AC. 1620110-30 as shown in the figure, the prism ABC-a1b1c1, AB ⊥. ∠ bcc1= 60182010-12 as shown in the figure, in the prism AB ⊥ BC-a/kloc-0. In the triangular prism ABC-a1B 1C1,AB=AC=5, BB 1=BC=6, and d and e are the midpoint of AA 1 and b1c, respectively (in the straight. A 1b 65438 prism ABC-a1b1c1d1,where the side BB 1C 1Cis is rhombic and the midpoint b1. In triangular prism ABC-a1b1c1,d and e are AB respectively; in triangular prism ABC-a1b10-27, bb/kloc-0. A 1A = AC = BC = 1。 A 1B = √ 2 (1) Proof: Plane A 1BC 18 is recommended to you: F.context('cmsRight') is especially recommended. [{ ' 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 ':' '，}])； 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 = 1720 134048；