NIMCET 2012 — Mathematics PYQ
NIMCET | Mathematics | 2012If the vectors a=(1,x,−2) and b=(x,3,−4) are mutually perpendicular, then the value of x is:
Choose the correct answer:
- A.
-2
- B.
2
- C.
4
- D.
-4
(Correct Answer)
-4
Explanation
1. Concept:
Two non-zero vectors a and b are mutually perpendicular (orthogonal) if and only if their dot product is equal to zero.
2. Calculation:
Given the vectors:
-
a=(1,x,−2)
-
b=(x,3,−4)
The dot product is calculated by summing the products of their corresponding components:
Set the dot product to zero for perpendicularity:
3. Solve for x:
Combine like terms:
Conclusion:
The value of x is −2.
Correct Option: (a)
Explanation
1. Concept:
Two non-zero vectors a and b are mutually perpendicular (orthogonal) if and only if their dot product is equal to zero.
2. Calculation:
Given the vectors:
-
a=(1,x,−2)
-
b=(x,3,−4)
The dot product is calculated by summing the products of their corresponding components:
Set the dot product to zero for perpendicularity:
3. Solve for x:
Combine like terms:
Conclusion:
The value of x is −2.
Correct Option: (a)

