De on luyen DH hay lam.

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"Q:GHI&AB)L'&1B45:$%YD,./ZC &$&AB)  =/7 4 /W  -/*  >/+ 7[\GX]^,F.X\H) )(100sin2100 Vtu π = / AU_`/a\bL)HGc\$&d%Q _ AU:e/f%&':[L))  / )( 10 ,50 4 F π − Ω 4 =/ )( 10 ,100 4 F π − Ω  >/ )( 10.2 ,100 4 F π − Ω  -/ +LC#cG!VLMG!V& gD]^,./0"Q  LC$ )L)Qc!V "Q    NW,.)g  =/ )(210 cm 4 / )(35 cm  -/ )(310 cm  >/,. 6LC)cG!V& D]-,hi^W./f"j!3k$  =/ 2 2A L)L  l 4 / 2 A L)L  m  >/ 2 2A L)L  m  -/ 2 A L)L  l <!"C'c1  !3LC9X7\LK/4\AU:b !"$ 9Q(Ln\(C)  /Wo 4 -/o  >/o  =/<o ?!"\Q LC&D   /N%9pQ\LqN 4 >/4%1:pQN  -/UpQ2  =/A(pQ2 rc$_G%%`G%%%Vb$4!M$X6/]+X+7/ s *W tX]*/ < /uG)rG%&&B)  -/*X7/  / 4 =/*X7/ < /  /X7/ ? /  >/X7/ < / 0Q-L)=&AT!M$v$!3GXK4AX4!M$)/ 4Ae&/Q%-7X%=*7wLM4A45  =/ 4 -/  /  >/s 0&)XLCeQ3G(%UALC  -/e 4 /$%&'x_  =/45  >/$%&'M_ *%Vby21:T&1$$\y-]+  X $$$%&'(QJ45I$\y/\_:21)g  /X7 2 4 -/ 2  >/ 3   =/X7 WQ24!M$)!3AH$Q  -/NWH 4 >/2AH  /2AWH  =/2AH 7!"bC$]7y%LCy1QLd&%\LM 4%)/=\LCT%LC1X7X'1$A(7/)yk:1)  -/4 /  >/7  =/< +z:LCy1QL!"y%b9dQ(C)  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[\GX[e!3X\H)] 2120 ^,Z./ @[  ]<•T[  ]*• _AU:45/_:SLM%&' $)  =/<<` 4 -/W`  /?+`  >/WW` ZC%-=y_1UN&qE&A)T%LCW7/fOAL'&1 :_1Xe€LCL))X!"_NL}&q&A)L)_GWHNJH/0A(: _1)  >/ 4 /  -/X7  =/7 FQ%u  Xu  5&A&U1L)d4A_1U$U>]7G/@N %9u  \_145/QN:u  Xu  &K N%Ou  u  )g  -/6 4 =/+  /*+  >/7W *0&1%%Vb:•B!3N%OLB% )/0&NOQXad4ALMLB&BL)%LB&BH!3+ L)$4ALB%;  -/?LB 4 /6LB  >/LB  =/<LB W&Vc$\OL))ZX]+X+7/ s*W tX]*/ < /=!M $b_:&Vc)$QG%&)  >/*/W+/ s  4 /+X/ s   =/7X7/ s   -/WX+</ s  7!" y!VX!"$\H!V_N: &!Vx H/f!V!"$)  /!VHq 4 -/!D%'!3  =/!VHv  >/!VG{ +0&%%G%D$_MX!"_Jg  -/u)GHNX&)GHS 4 >/[)BL‚IM  =/u)GHSX&)GHN  /u)BL‚IM 60&%% _X!3T&!)b%%)  >/0H%% 4 =/ZC%%  -/!"%%  /=A:$%% <[\GX[]7•X]/ sW ^,ƒ./F\H$4QS) )(100sin100 Vtu π = XBHN$e!3/ZMO%&':_)$% &':Nj %&'_x_)  =/` 4 -/7`  >/7`  /` ?01_)BGN)1_:IL)&Vc  >/•%_14 -/@N2BDA&_  /$%U„  =/)G%y_ *=QS1:U&$y]…  ,^/ + .,./0"Q2!39 452!3HA)  =/X+7/ s6 ,. 4 >/7/ s6 ,.  /X7/ s6 ,.  -/X7/ s6 ,. *! LwX4\[]•X]^,†ƒ.X‡]7F|Xˆ - ]ZXˆ = ] 2 ZX - L) = G7^/0 ;    >/^,F. 4 -/ )(/3 H π  /^,F.  =/^,F. *LC%T&!M!VH$A(‡]s  XNK45ILC/ @N%OLCL)!V)g  -/ 4 =/7  >/  /7 **%#!3!vBQG%&BGB4ck!M/%# !"L9:c_B/=\!‰cL)!‰LMB$H!3) s ,`  .L),`  ./ Z'&14bHBN%%#  / 4 -/  >/  =/X *WZC1:%N$A(7/@N%OLC1L)G$Qe97\ 7X7/%$QUGN:LC%%N  /7X7\LK 4 =/7X7\77  -/X77\LK  >/77\LK *70&X\O4NUL)1:U4\A)KH L)  /KG 4 =/G^  -/!3G  >/G^W *+TLC%&N9‡\‡&!M!VHq N:LCy!V)  /NNXKXxVLC 4 -/NCXKXMVLC  =/NNXKXMVLC  >/NCX!3XMVLC *6[\G$1N%XOA%%\NH # \C)B)  >/_AU2\(&vN 4 /GO\HNL)\HN  -/0e&dNX$2  =/GO\HUL)\HN *<!VHq4%1[!3T5XTGND!MA/eHL)!V_ x&$\_/0A(!V!V:!V$)  =/ 1 + n nR 4 / 1 + n R  >/ 2 nR  -/ n R 2 *?=A:!‰4SGUL)  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!V* N45LC/0A(:!V)  >/ 4 /*  -/  =/7 W$9&A3B$ )(20cos) 23 sin(2 cmt x u π ππ += X&$) "Q:GHI&AB)L'&1B45:$%YD,./ZC &$&AB)  =/7 4 /W  -/*  >/+ 7[\GX]^,F.X\H) )(100sin2100 Vtu π = / AU_`/a\bL)HGc\$&d%Q _ AU:e/f%&':[L))  / )( 10 ,50 4 F π − Ω 4 =/ )( 10 ,100 4 F π − Ω  >/ )( 10.2 ,100 4 F π − Ω  -/ +LC#cG!VLMG!V& gD]^,./0"Q  LC$ )L)Qc!V "Q    NW,.)g  =/ )(210 cm 4 / )(35 cm  -/ )(310 cm  >/,. 6LC)cG!V& D]-,hi^W./f"j!3k$  =/ 2 2A L)L  l 4 / 2 A L)L  m  >/ 2 2A L)L  m -/ 2 A L)L  l <!"C'c1  !3LC9X7\LK/4\AU:b !"$ 9Q(Ln\(C)  /Wo 4 -/o  >/o  =/<o ?!"\Q LC&D   /N%9pQ\LqN 4 >/4%1:p QN  -/UpQ2  =/A(pQ2 rc$_G%%`G%%%Vb$4!M$X6/]+X+7/ s *W tX]*/ < /uG)rG%&&B)  -/*X7/  / 4 =/*X7/ < /  /X7/ ? /  >/X7/ < / 0Q-L)=&AT!M$v$!3GXK4AX4!M$)/ 4Ae&/Q%-7X%=*7wLM4A45  =/ 4 -/  /  >/s 0&)XLCeQ3G(%UALC  -/e 4 /$%&'x_  =/45  >/$%&'M_ *%Vby21:T&1$$\y-]+  X $$$%&'(QJ45I$\y/\_:21)g  /X7 2 4 -/ 2  >/ 3   =/X7 WQ24!M$)!3AH$Q  -/NWH 4 >/2AH  /2AWH  =/2AH 7!"bC$]7y%LCy1QLd&%\LM 4%)/=\LCT%LC1X7X'1$A(7/)yk:1)  -/4 /  >/7  =/< +z:LCy1QL!"y%b9dQ(C)  =/NCX!3LC 4 /NNX!3LC  -/NCXKLC  >/NNXKLC 6b#D{SXH!M$LC)LM4A/0RO(( L)(Q%UL)Q&c&y%& )**/_]^  ]  /0H )  -/X7F| 4 =/X7F|  /X7F|  >/X7F| <F!3)BQ1_:%%  >/F!3)yGeL:F& 4 -/F!3%b%%  =/F!3y}  /F!3y ?~b)T&!1:BGB4!3B  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-/6 4 =/+  /*+  >/7W *0&1%%Vb:•B!3N%OLB% )/0&NOQXad4ALMLB&BL)%LB&BH!3+ L)$4ALB%;  -/?LB 4 /6LB  >/LB  =/<LB W&Vc$\OL))ZX]+X+7/ s*W tX]*/ < /=!M $b_:&Vc)$QG%&)  >/*/W+/ s  4 /+X/ s   =/7X7/ s   -/WX+</ s  7!" y!VX!"$\H!V_N: &!Vx H/f!V!"$)  /!VHq 4 -/!D%'!3  =/!VHv  >/!VG{ +0&%%G%D$_MX!"_Jg  -/u)GHNX&)GHS 4 >/[)BL‚IM  =/u)GHSX&)GHN  /u)BL‚IM 60&%% _X!3T&!)b%%)  >/0H%% 4 =/ZC%%  -/!"%%  /=A:$%% <[\GX[]7•X]/ sW ^,ƒ./F\H$4QS) )(100sin100 Vtu π = XBHN$e!3/ZMO%&':_)$% &':Nj %&'_x_)  =/` 4 -/7`  >/7`  /` ?01_)BGN)1_:IL)&Vc  >/•%_1 4 -/@N2BDA&_  /$%U„  =/)G%y_ *=QS1:U&$y]…  ,^/ + .,./0"Q2!39 452!3HA)  =/X+7/ s6 ,. 4 >/7/ s6 ,.  /X7/ s6 ,.  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*70&X\O4NUL)1:U4\A)KH L)  /KG 4 =/G^  -/!3G  >/G ^W *+TLC%&N9‡\‡&!M!VHq N:LCy!V)  /NNXKXxVLC 4 -/NCXKXMVLC  =/NNXKXMVLC  >/NCX!3XMVLC *6[\G$1N%XOA%%\NH # \C)B)  >/_AU2\(&vN 4 /GO\HNL)\H N  -/0e&dNX$2  =/GO\HUL)\HN *<!VHq4%1[!3T5XTGND!MA/eHL)!V_ 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