AP EAMCET2006MathematicsVector Algebra
If the volume of parallelopiped with conterminus edges 4 i +5 j + k ,- j + k and 3 i +9 j +p k is 34 cubic units, then p is equal to :
Options
- A4
- B-13
- C13
- D6
Correct answer
B. -13
Step-by-step solution
Coterminus edges of a parallelopiped are 4 i +5 j + k ,- j + k and 3 i +9 j +p k Volume of parallelopiped =34 | array rrr 4 & 5 & 1 0 & -1 & 1 3 & 9 & p array |=34 4 | array cc -1 & 1 9 & p array |-5 | array cc 0 & 1 3 & p array |+1 | array cc 0 & -1 3 & 9 array |=34 4(-p-9)-5(-3)+1(3)=34 -4 p-36+15+3=34 4 p=-36+18-34 p=- 52 4 =-13