Mea Fa'atelega Fa'alava e Fa'aaogaina ai Vaega Veketo o le Iunite
E mafai ona tatou fuafuaina sa'o le cross product pe afai tatou te iloa vaega o vectors. E tutusa le faiga ma le dot product . Muamua, tatou te fa'ateleina unit vectors i , j , ma le k . O le vector product i le va o unit vectors tutusa e zero.
i x i = j x j = k x k = 0
I le faasino i le fua faatatau o le faateleina o vector na maua muamua (A x B = AB agasala θ) ma le meatotino e tete'e i le fesuia'iga o fa'atelega veketo (A x B = – B x A), ona tatou maua lea:
i x j = -j x i = k
j x k = -k x j = i
k x i = – i x k = j
O lea la ua tatou faʻaalia vectors A ma le B i tulaga o a la vaega, vaevaeina a la oloa ma faʻaaoga le oloa o vectors iunite.
A x B= (Axi + Ayj + Azk) x (Bxi + Byj + Bzk)
A x B = Axi x Bxi + Axi x Byj + Axi x Bzk +
Ayj x Bxi + Ayj x Byj + Ayj x Bzk +
Azk x Bxi + Azk x Byj + Azk x Bzk
A x B = AxBx (i x i) + AxBy (i x j) + Ax Bz (i x k) +
AyBx (j x i) + AyBy (j x j) + AyBz (j x k) +
AzBx (k x i) + AzBy (k x j) + AzBz (k x k)
Karena i x i = j x j = k x k = 0 Tanu i x j = –j x i = k, j x k = –k x j = i, k x i = -i x k = j, o lea la:
A x B = AxBx (0) + AxBy (k+ Ax Bz (-j+
AyBx (-k+ AyBy (0) + AyBz (i+
AzBx (j+ AzBy (-i+ AzBz (0)
A x B = AxBy (k+ Ax Bz (-j+
A y B x ( -k ) + A y B z ( i ) +
A z B x ( j ) + A z B y ( -i )
A x B = AxBy (k+ Ax Bz (-j+ AyBx (-k+ AyBz (i+ AzBx (j+ AzBy (-i)
A x B = (AyBz - AzBy)i + (AzBx - Ax Bz)j + (AxBy - AyBx )k
Afai o le C = A x B o vaega ia o le C e faapea:
Cx = A y B z – A z B y
Cy = A z B x – A x B z
Cz = A x B y – A y B x