Please help me with these problems?

Question

It can be shown that the cross product of two vectors, A = Ax i + Ay j + Az k, and B = Bx i + By j + Bz k is as follows:
A * B = (AyBz - AzBy) i + (AzBx - AxBz) j + (AxBy - AyBx) k

The cross product can then be written as follows, where we use the rules for evaluating a determinant. (Note, however, that this is not actually a determinant, but a memory aid.)

| i j k |
A * B = | Ax Ay Az |
| Bx By Bz |

Assume that A = 7.2 i - 4.3 j and B = -8.5 i + 7.0 j + 2.0 k.

(a) Use the above results to determine the vector product A x B.
i + j + k
(b) Use the above results to determine the angle between A and B.

Answer 1

i dont remember becoz i did such question long time ago..

but i will give u hints...

A=7.2i -4.3j+0k

B=-8.5i+7j+2 k

now Ax B =

determinant of
i j k
7.2 -4.3 0
-8.5 7 2


solve it and we will get a vector C

now AxB=AB sinσ

since we know AxB=C and find A(magnitude) and B(Magnitude)

magnitude of a vector is =√(Ax²+Ay²+Az²)
similary for B.

doing that...solve AxB=ABsinσ and find angle σ..hope it has helped u...

Answer 2

and getting this answer will prove what?