Wednesday

November 26, 2014

November 26, 2014

Posted by **Mathwise** on Wednesday, November 4, 2009 at 6:33am.

find: Ax(BxC)

pls help with solution.

- Vector & Geometry -
**Reiny**, Wednesday, November 4, 2009 at 7:44amA=[1,1,0]

B=[2,-3,1]

C=[4,0,-3]

Let's do BxC

I use a very simple algorith to form the cross-product of two vectors.

- write the two vectors above each other

2 -3 1

4 0 -3

- for the first number, with your pinkie or with a pencil, block off the first column and find the right cross-product of the remaining square matrix, that is, (-3)(-3) - (0)(1) = 9

-for the second number, with your pinkie or withe a pencil, block off the middle column and find the**negative**right cross-product of the remaining matrix, that is

-( (2)(-3) - (1)(4) ) = 10

- and finally for the third number, block off the third column and find the right cross-product of the remaining square matrix, that is, (2)(0) - (-3)(4) = 12

So BxC = [9,10,12]

( I always check by taking the dot product of this with the two original vectors, you should get zero)

Now repeat by taking [1,1,0]x[9,10,12]

I got [12, -12, 1} or 12i - 12j + k

**Answer this Question**

**Related Questions**

Physics (vectors) - Given vectors A= (Axi + Ayj), B= (Byj+Bzk) and C= (Cyj + Czk...

Calculus and vectors - Vector AB is a vector whose tail is at (-4,2) and whose ...

Calculus and vectors - Vector AB is a vector whose tail is at (-4,2) and whose ...

Vectors and Geometry - if A=i+j, B=2i-3j+k and C=4j-3k find (i) (AxB)xC & Ax(BxC...

Vectors and Geometry - if A= i+j, B=2i-3j+k and C=4j-3k find (i) (AxB)xC (ii) Ax...

Vectors - Cross product of vector: If axb(cross product)=(2,0,1) and bxc= -4,0,-...

Help on Vectors & Geometry - (a) Given that A= 3i - j + 2k and B=2i + 3j - k ...

Calculus - Dot Product - consider a rhombus ABCD a) find the resultant of vector...

jane - 1. a centripetal-acceleration addict rides in uniform circular motion ...

Precalc - Given the plane 3x+2y+5z=54 and the points P0(6, 8, 4)[on plane] and ...