NIMCET 2013 — Mathematics PYQ
NIMCET | Mathematics | 2013The area of the parallelogram whose diagonals are a=3i^+j^−2k^ and b=i^−3j^+4k^ is:
Choose the correct answer:
- A.
103
- B.
53
53
Explanation
Solution
1. Formula for Area using Diagonals:
When the diagonals of a parallelogram are given as vectors d1 and d2, the area is:
Area=21∣d1×d2∣
2. Calculate the Cross Product (a×b):
a×b=i^31amp;j^amp;1amp;−3amp;k^amp;−2amp;4
a×b=i^(4−6)−j^(12−(−2))+k^(−9−1)
a×b=−2i^−14j^−10k^
3. Calculate the Magnitude of the Cross Product:
∣a×b∣=(−2)2+(−14)2+(−10)2
∣a×b∣=4+196+100
∣a×b∣=300
∣a×b∣=103
4. Calculate the Final Area:
Area=21×103
Area=53
Explanation
Solution
1. Formula for Area using Diagonals:
When the diagonals of a parallelogram are given as vectors d1 and d2, the area is:
Area=21∣d1×d2∣
2. Calculate the Cross Product (a×b):
a×b=i^31amp;j^amp;1amp;−3amp;k^amp;−2amp;4
a×b=i^(4−6)−j^(12−(−2))+k^(−9−1)
a×b=−2i^−14j^−10k^
3. Calculate the Magnitude of the Cross Product:
∣a×b∣=(−2)2+(−14)2+(−10)2
∣a×b∣=4+196+100
∣a×b∣=300
∣a×b∣=103
4. Calculate the Final Area:
Area=21×103
Area=53
