... (36)lex) = ~sin(2asin ax) - 2a2[1 + 4a4 cos2 (ax)] cos(ax) cos x4+ 2a3[1 + I2a4 cos2 (ax)]sin(ax) (2 + sin x)+ ~a[sin(ax) + ax.cos(ax)]sin(2ax.sin ax), a =77:/ 6 (4.45). 2 Nghi~m chinh xac ... ui(L)=O ,2: ::;i:::;N,1[AI)k 1a=- K+-+- A= 2 2 ' jJ ,a f t (f t) EF 1+ ~(M )2 M~ =P(ti)' ui(x)=u(x,tJ, Gi =G(ui-i(O),ui -2( O),Pi-j,Pi -2) ' (2 + AM)ui-l - ui -2 1Fi(X) = 2 +2fi(X), ... thucpTHlnh 2. 4. Quan M crl- El 2 ~"-~-~Ir~ cr,-'ti . crcr,1.0'--L5-1-11500510rLLpHinh 22: H~ dim 3 thanhHlnh 2. 5. Quan h~ cr2- E2 2. lx1d_T~nh~_! 2 .t ! -.crT+.k.",,(I',.,)1~i...