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Question #41878
The Question
Let , , and . For , let denote the standard basis vectors respectively. Let be the vector projection of onto . Define the vectors for . If is the volume of the parallelepiped determined by , find the value of .
Options
- A.
144
- B.
324
- C.
18
- D.
8
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Bridge
Practice problems that bridge the gap between foundational theory and advanced practical application.
Concepts Behind This Question
Sigma Notation Properties|Linear Independence vs Dependence|Dot Product Projection Sign
Why This Question Is Tricky
Common Mistakes
This question tests the student's ability to distinguish between a dot product and the magnitude of a vector projection in a summation basis.
The trap lies in assuming , which ignores the absolute value sign inherent to vector magnitude.
If a student makes this error, the coefficient matrix becomes , leading to the incorrect volume .
Recognizing that the projection magnitude forces all scalar coefficients to be strictly positive changes the linear transformation matrix, correctly yielding a volume of 144.
Quick Facts About This Question
Question Information
| Subject | Mathematics |
| Chapter | Sequences and Series - Class 11 |
| Concept | Sigma Notation Properties |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |