§1矢量代数与张量初步 ■矢量定义=AA2A=A,A 直角坐标系中A=Ai+Aj+Ak A=∑4A=团=(4++4)=∑4 ■矢量的基本运算 AB=2AB =AB cose Ax B=ABsin e, A A2A, BBB§1 矢量代数与张量初步 A A A AA A A A    = = = ˆ , , ˆ 直角坐标系中 A A i A j A k = + + z y z 3 1 i i i A A e = =  3 1 2 2 2 2 2 1 2 3 1 ( ) i i A A A A A A = = = + + =  矢量定义 矢量的基本运算 3 1 cos i i i A B A B AB  =  = =  1 2 3 1 2 3 1 2 3 sin n e e e A B AB e A A A B B B  = = 