Friday Dec 14, 2007
They say nothing lasts forever. After working for Sun five and half years, I decided to pursue another opportunity outside the company.
Sun is my first employer right after I graduated from college. I really enjoyed my time here at Sun China ERI. It's my pleasure to have chance to work with you. Thanks everyone for your support, guidance and encouragement during the past years. I'll treasure all the memories during daily work, club activities, luncheons, and table football games.
This world is small. No doubt our paths will cross again one day. Look forward to working with you gain. Good luck to you all. Take care and keep in touch.
Thursday Dec 06, 2007
After I wrote the blog about solving the "World's Hardest Easy Geometry Problem", I got my highest page hits ever (check the snapshots, took around 21:40 Dec 6, 2007 CST). But it's weird that my blog was not listed on Popular Blogs of http://blogs.sun.com.
Wednesday Dec 05, 2007
There's a famous "World's Hardest Easy Geometry Problem" in http://thinkzone.wlonk.com/MathFun/Triangle.htm, It's solved now. Here is the step by step for the solution.
Figure 1
From Figure 1, we have
[1] AC = BC
[2] BD = CD
Figure 2
In Figure 2, parallel to AB, we draw DF
Because [1] and AB||DF, we get
[3] DC = FC
[4] AD = BF
Figure 3
In Figure 3, we draw line AF.
From [4], and AB=BA, and angle DAB = FBA (=80),
the triangle ABD equals to triangle ABF. So
[5] AF = BD
From [2], AF = CD
From [3], we get
[6] AF = CF
So CAF = 20, EAF = 10, FAB = 60,
[7] DGF = 60
[8] AB = BG = GA
From [5], [7] and [8], we get
[9] DF = FG = GD
Figure 4
In Figure 4, we draw FH vertical to AC.
From [6] and angle CAF = ACF, we get triangle AFH equals to triangle CFH. So
[10] AH = CH
Figure 5
In Figure 5, we draw CI.
From [10] and FH vertical to AC, we get
[11] angle DCI = DAI = 10
[12] CI = AI
From [11], we get
[13] angle FCI = 10 = DCI
[13'] angle FCI = FAI
Figure 6
In Figure 6, extend CI to AB.
From [13], and angle ABC = BAC = 80, we get
line CI vertical to AB,
[14] line CI is the same as line CG
From [12], [13], [14], we get triangle CEI equals to triangle AGI. So
[15] EI = GI
From [12], [15], we get
[16] CG = AE
From [13'], [16], we get triangle CGF equals to triangle AEF. So
[17] EF = FG
Finally
From [9], [17], we get
[18] EF = DF
Because DF || AB, so
[19] angle CFD = CBA = 80
From [18], [19], we get
[20] angle DEF = EDF = 50
So angle X = angle DEF - angle AEF
= 50 - (180 - 70 - 60 - 20)
= 50 - 30
= 20
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Stay in touch. You'll always be part of the famil...
I will. Thanks!
Yeah, the world is small, and the best wishes...
Wish you all the best in the future. :-) keep in t...
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keep in touch
simford, I saw your blog until now,but I still giv...
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