NIMCET 2015 — Mathematics PYQ
NIMCET | Mathematics | 2015If a=4i^+6j^ and b=3i^+4k^, then the vector form of the component of a along b is:
Choose the correct answer:
- A.
10318(3i^+4k^)
- B.
518(3i^+4k^)
- C.
318(3i^+4k^)
- D.
318(3i^+4k^)
(Correct Answer)
318(3i^+4k^)
Explanation
1. Formula:
The vector component (projection) of a along b is given by:
Vector Component=(∣b∣2a⋅b)b
2. Finding Dot Product (a⋅b):
a=4i^+6j^+0k^
b=3i^+0j^+4k^
a⋅b=(4×3)+(6×0)+(0×4)
a⋅b=12+0+0=12
3. Finding Magnitude Squared (∣b∣2):
∣b∣=32+02+42
∣b∣=9+16=25=5
∣b∣2=25
4. Final Solving:
Vector Component=(2512)b
Vector Component=2512(3i^+4k^)
Conclusion:
Correct option is (d).
Explanation
1. Formula:
The vector component (projection) of a along b is given by:
Vector Component=(∣b∣2a⋅b)b
2. Finding Dot Product (a⋅b):
a=4i^+6j^+0k^
b=3i^+0j^+4k^
a⋅b=(4×3)+(6×0)+(0×4)
a⋅b=12+0+0=12
3. Finding Magnitude Squared (∣b∣2):
∣b∣=32+02+42
∣b∣=9+16=25=5
∣b∣2=25
4. Final Solving:
Vector Component=(2512)b
Vector Component=2512(3i^+4k^)
Conclusion:
Correct option is (d).