Question

If `A= <-3 ,4 ,-1 >` and `B= <8 ,-4 ,2 >`, what is `A*B`?

Answer 1

`-42`

Explanation:

given 2 vectors `ula = (x_1,y_1,z_1) " and ulb=(x_2,y_2,z_2)`

then `ula . ulb = (x_1xxx_2)+(y_1xxy_2)+(z_1xxz_2)`

here `A = (x_1,y_1,z_1) = (-3,4,-1)`

and `B =(x_2,y_2,z_2) = (8,-4,2 )`

`rArr A . B = (-3xx8)+(4xx-4)+(-1xx2)`

= - 24 - 16 - 2 = - 42