write xy as the sum of unit vectors for x (8,2,negtive 9) nd y (negative 12,negtive 1, 10). my ans was negative 4i plus j plus k. wrong can you correct it for me please . thank you.
The sum of vectors x and y would not be written "x y". What kind of product are you talking about? Cross (dot) prducts are scalars. Are you taking about the vector cross product X x Y ? (The characters and x operator are supposed to be in bold type for cross products)
Your answer 4i + j + k IS the correct SUM of x and y.
The vector (cross) product of x and y is the determinant of
| i j k |
| 8 2 -9 |
|-12 -1 10|
which equals
= 29 i +28j +16k
