Solve Vector Equation Problem: A, B, C & AxB + AxC

[jean014]

hello!

im new here and i just need a little help in solving this problem:
its a set of vector equation:

A = ai + bj + cK
B = -2i +j - 4K
C = i + 3j +2k

where A is an unknown vector. If

(AxB)+(AxC) = (5a + b)i + (3b-2)j + (-4c+1)k

i need to solve for a,b,c..

pls pls pls.. help! >.<

thanks

 

[jean014]

solving vector eqns using matrix inversion

hello!

im new here and i just need a little help in solving this problem:
its a set of vector equation:

Homework Statement

A = ai + bj + cK
B = -2i +j - 4K
C = i + 3j +2k

where A is an unknown vector. If

(AxB)+(AxC) = (5a + b)i + (3b-2)j + (-4c+1)k

i need to solve for a,b,c..

Homework Equations

matrix inversion by co-factor mtd or LU decomp..

The Attempt at a Solution

i don't even know where to begin!

pls pls pls help..

just on how to start .. or the algo ill finish the rest >.<

thnx!

 

[D H]

To start you should calculate A\times(B+C). You know B and C and have an expression for A.

 

[HallsofIvy]

hello!

im new here and i just need a little help in solving this problem:
its a set of vector equation:

A = ai + bj + cK
B = -2i +j - 4K
C = i + 3j +2k

where A is an unknown vector. If

(AxB)+(AxC) = (5a + b)i + (3b-2)j + (-4c+1)k

i need to solve for a,b,c..

pls pls pls.. help! >.<

thanks

Looks a lot like homework to me- so I'm going to move it to the "Homework- calculus and beyond" folder.

And, of course, you will have to make an effort yourself: What are AxB and AxC? That should be your first step. Then add those two and set them equal to the right hand side above. That will give you three equations to solve for a, b, c.

 

[D H]

This is exactly the same problem as https://www.physicsforums.com/showthread.php?t=188267. They should be merged. Jean, you are not supposed to post the same thing in multiple threads.

 

[HallsofIvy]

This is exactly the same problem as https://www.physicsforums.com/showthread.php?t=188267. They should be merged. Jean, you are not supposed to post the same thing in multiple threads.

Thanks. I will.

(It was in "Engineering, Computer Science, and Technology"?? No wonder I didn't find it!)