30 C\u00e2u tr\u1eafc nghi\u1ec7m v\u1ec1 t\u1ecda \u0111\u1ed9 \u0111i\u1ec3m v\u00e0 vect\u01a1 trong kh\u00f4ng gian (c\u00f3 \u0111\u00e1p \u00e1n)<\/a><\/blockquote><\/iframe>