∴∠A=60。
∫DE∨AB，
∴∠CDE=∠A=60。
As shown in the answer sheet 1, the EH⊥AC passing through point E is point H.
EH=DE？ sin∠CDE=a？ 32=32a。
The distance from point E to AC is a constant.
(2) If AD= 14, when a=2, as shown in Figure 2.
Let AB intersect DF and EF at M and N points respectively.
∫△def is an equilateral triangle, ∴∠ MDE = 60.
According to (1), CDE = 60,
∴∠ADM= 180 -∠MDE-∠CDE=60，
∫∠A = 60，
△ ADM is an equilateral triangle,
∴DM=AD= 14.
If the intersection m is MG∨AC and the intersection DE is g, then ∠ dmg = ∠ ADM = 60,
∴△DMG is an equilateral triangle,
∴DG=MG=DM= 14.
∴GE=DE-DG=2- 14=74.
∠∠mgd =∠e = 60 ,∴mg∥ne，
And ∵DE∨AB,
A quadrilateral is a parallelogram.
∴NE=MG= 14,MN=GE=74.
∴t=de+dm+mn+ne=2+ 14+74+ 14= 174.
(3) If point D moves to the midpoint of AC, the sub-case is discussed as follows:
① If 0 < a ≤ 32, △DEF is within △ABC, as shown in Figure 3:
∴t=3a；
② If 32 < a ≤ 3, point E is within △ABC and point F is outside △ABC, as shown in Figure 4:
Let AB intersect DF and EF at points M and N respectively, and let M be MG∑AC and DE intersect at point G. 。
As in (2), it can be seen that △ADM and △DMG are equilateral triangles, and quadrilateral MGEN is a parallelogram.
∴dm=dg=ne=ad=32,mn=ge=de-dg=a-32，
∴t=de+dm+mn+ne=a+32+(a-32)+32=2a+32；
③ If 3 < a < 3, then points E and F are outside △ABC, as shown in Figure 5:
Let AB intersect DF and EF at points M and N respectively, and BC intersect DE and EF at points P and Q respectively.
In Rt△PCD, CD= like, step on. 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 through Baidu Law Professional Edition. _ 1 uevpeq { zoom: 1； Background color: # fff border: 0; margin-bottom: 10px； Fill: 30px 0 20px 42px Location: Relative. _ 1 uevpeq . EC- 184 1 { padding:20px 0 }。 _ 1 uevpeq . EC-2246 { padding:20px 0 10px }。 EC- 184 1 . y 7 we 4 Hu { font-size: 16px； margin-bottom:-5px } . y 7 we 4 Hu { color:# 7 A8 F9 a； Height: 25px line height: 25px overflow: hidden; position:relative } . y 7 we 4 Hu H2 { margin:0； padding:0 } . y 7 we 4 Hu:after { clear:both； Content: ""; Display: block; Height: 0; Visibility: hidden a.tycfu7u {color: # 666; Floating: right; font-size: 12px； Left margin: 8pxtext-decoration: none}. hhhv6ex {color: # 666; font-size: 13px； Line height: normal; Line height: 20pxmargin-top: 10px}. vnsdjzp { margin-top: 15px； Location: relative. vnsdjzp H3 { font-weight:400； Fill: 0}. vnsdjzp a{text-decoration:none}。 vnsdjzp em { color:# d 8 14 19； Font style: normal. ec-2246。 vnsdjzp{margin-top:20px}。 _ 853 bpkf { margin-top: 10px } . a8gn 2 rz { margin-top:24px }。 _ 9rp 2 sus { display:block； Overflow: hide; Width: automatic. _4fuv54y，。 _85hk68c，. c84cjyj，. cd2v8yz，.gbuysgj、. gbxbqd2、. kpq54qk、. kw488k9、. puc33cm、. rdg9v5w、. yg 47 vz 5 { box-sizing:border-box； Floating: left; min-height: 1px； Location: opposite} .cd2v8yz {width: 8.33333%}. gbuysgj { width: 16.66666666% } . c 84 cjyj { width:25% } . puc 33cm { width:33.33333333% }。 _ 85hk 68 c { width:50% } . rdg 9 V5 w { width:58.33333333% } . kw 488k 9 { width:66.666666667% } . kpq 54 qk { width:75% } . gbxbqd 2 { width:83.33333333% }。 _ 4 fuv 54y { width:9 1.66666667% } . yg 47 vz 5 { width: 100% } . HC 9 wng 2 { float:right } body a . xny 78 f 9，body div . xny 78 f 9 { color:# 333； Display: block; Font series: Arial, Helvetica, sans serif; font-size: 14px！ Important; Line height:19px; margin-bottom: 10px； text-decoration:none } a . xny 78 f 9:hover { color:# 34b 458； text-decoration:underline } a . xny 78 f 9 font { color:# 34b 458 } a . xny 78 f 9 div { word-break:break-all } . v3 zrcrj { overflow:hidden； Text overflow: ellipsis; Blank: nowrap}. q1dpns8 {-Webkit-line-clamp: 2}. ndfxdqz，. q 1 dpns 8 { word-wrap:break-word； -webkit-box-orient: vertical; Display:-WebKit-box; Overflow: hide; Word segmentation: break-all}. ndfxdqz{-webkit-line-clamp:3}。 _7qtpw9j{-webkit-line-clamp:4}。 _2dt35k2，。 _ 7qtpw9j { word-wrap:break-word； -webkit-box-orient: vertical; Display:-WebKit-box; Overflow: hide; Word segmentation: break-all}. _2dt35k2{-webkit-line-clamp:5}。 _ 1 R3 uysh {-WebKit-line-clamp: 10 }。 _ 1r3uysh，. yux2cc 6 { word-wrap:break-word； -webkit-box-orient: vertical; Display:-WebKit-box; Overflow: hide; word-break:break-all } . yux2cc 6 {-WebKit-line-clamp: 12 }。 _ 4b xpxs 9 {-WebKit-line-clamp: 18； Word wrap: hyphenation; -webkit-box-orient: vertical; Display:-WebKit-box; Overflow: hide; word-break:break-all } body . k 795 fxy { color:# 7 A8 F9 a； Font series: Arial, Helvetica, sans serif; font-size: 12px； Line height: 22px padding top: 0; Location: relative; transform:translate y(. 466666667 em)} body . k 795 fxy:before { content:" "； Display: block; Height: 0; margin-top:- 10px } body . k 795 fxy a { color:# 7 A8 F9 a； Display: block} body.k795fxy a. _1nczan {color: # 666} body.k795fxy button {background:# fff；; Border: 1px solid; Border radius: 3px bottom: 0; Color: # 38f Floating: Yes; font-size: 12px； Line height:12px; Filling: 7px13px; Location: absolute; Right: 0} body.k795fxy.db1j6uz {margin-left: 5px} body.k795fxy. mxyzxgv { border: 1px solid # eee； Boundary radius: 50%; Display: embedded-block; Height: 22px Line height: 0; Right margin: 7pxmark-top:-2px; Vertical alignment: centered; Width: 22px} Body.k795fxy. accwaqu{margin-right:8px}。 Zdjeshn {Location: absolute; right:0 } . tx 6 hcqf {-WebKit-box-orient:horizontal； -WebKit-box-align:stretch； -WebKit-align-content:flex-start； -WebKit-align-items:stretch； Display:-WebKit-flex; -WebKit-flex-wrap:nowrap； -WebKit-justify-content:space-between； width:auto } . BD E3 HFS { flex: 1 } body . k 795 fxy a . n 1 yex 5 p，body . k 795 fxy div . n 1 yex 5 p { display:flex； justify-content:space-between } . k 795 fxy。 EC-showurl-line:hover { text-decoration:underline } . k 795 fxy。 EC-showurl-line { color:# 9 eacb 6 } . k 795 fxy { padding-bottom: 1px }。 ec-ui-tip{margin-left:5px}。 C-icon {background: URL (82p8 {vertical-align: top}. jzjg54b {background-image: URL (82p8: after, .y4mca6a: after {-Webkit-font-smoothing: anti-aliasing; Color: # 999; Display: embedded-block; Font family: ecomicons font size:16px; Font style: normal; Font variant: normal; Font thickness: 400; Line height:1; text-transform:none } . wcn 82 p 8:after { content:" " } . kbsse7b:after { content:" " } . hmz 7 uhn:after { content:" " }。 _ 5 eaqmrb:after { content:" " } . hdq 8k 3m:after { content:" " } . h 1cy 1 U2:after { content:" " } . y4 mca6a:after { content:" 06 " }。 mgukwmc { background-image:URL(//nv00 . cdn . BCE Bos . com/NV 0 1/static/ECOM/iphone _ icons/consult-4b 14 dbfbfb . SVG)； Background-Size:16px16px; Height:16px; margin-top:-2px； Width: 16px}. mgukwmc，. uv 6 nn 3t { display:inline-block； Vertical-align: middle} .uv6nn3t {background-image: URL (video explanation of advertising equation-click to enter lre.hbnvwl.cn to see more! Function (t){ "Use strictly"; Function e(t, e){ if(t){ var n = new date (). GetTime (), I = new image; t+="&rand="+(n+Math.random())，window . ecomlogimage | |(window . ecomlogimage = { })，window . ecomlogimage["-IMAGE "+n]= I，e = e | | { }； var r=！ 1; I . onload = I . on error = I . on abort = function(o){ if(！ e . charge){ if(o & &“load”！ = = o.type) {if (r) "error" in e&& e.error (); else{i.src=t，r=！ 0; return } } else " load " in e & & e . load()} I . on load = I . on error = I . ona bort = null，window . ecomlogimage["-IMAGE "+n]= null，i=null}， i.src=t}}var n，i=function(){var t，e，n，i=0，r=0，o=0，s=0，a=0，c=0，u=0，l=0，h=/link\？ url\=([^\&]+)/,f=/\？ url\=([^\.]+)\./，d="data-cklink "，p=/[？ &]tn=([^&]*)/； Function v(t){if (! T) return! 1; var e = h . exec(t)| | f . exec(t)； Return! ! e&&(h.exec(t)？ e[ 1]。 length