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The area (in sq. units) of the parallelogram whose diagonals are represented by the vectors a⃗=2i^−j^+k^\vec{a}=2\hat{i}-\hat{j}+\hat{k} and b⃗=3i^+4j^−k^\vec{b}=3\hat{i}+4\hat{j}-\hat{k}, is

Solution

✅ Correct Option: 4

When the diagonals are given, area =12∣a⃗×b⃗∣=\frac12|\vec a\times\vec b|.

(2,−1,1)×(3,4,−1)=(1−4, 3+2, 8+3)=(−3,5,11)(2,-1,1)\times(3,4,-1)=(1-4,\,3+2,\,8+3)=(-3,5,11).

Its magnitude is 9+25+121=155\sqrt{9+25+121}=\sqrt{155}, so the area is 1552\frac{\sqrt{155}}{2}.

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