... gi´o.iha.ncu’a d˜ay: 0, 2; 0, 22 ; 0, 22 2; ,0, 22 2 n, Chı’dˆa˜n. Biˆe’udiˆe˜n andu.´o.ida.ngan=0, 22 2= 2 10+ 2 10 2 + ···+ 2 10n(DS. lim an =2/ 9)108 Chu.o.ng 8. ... d˜a cho.Ta c´o−→M0M1= (2, 2) =2e1− 2e 2 ,⇒|−→M0M1| =2 √ 2 ⇒ e =M0M1|M0M1|=2e1− 2e 2 2√ 2 =1√ 2 e1−1√ 2 e 2 .trong d´o e1, e 2 l`a vecto.do.nvi.cu’a ... o(t 2 )=−x 2 2+x4 24 + o(x4) −1 2 −x 2 2+x44+ o(x4) 2 + o−x 2 2+x4 24 + o(x4) 2 = −x 2 2+x4 24 −x48+ o(x4)=−x 2 2−x4 12 + o(x4). V´ı d u.5....