Question

If a= 2i-3j+k,b=-i+k and c=2j-k. Find the area of parallelogram whose diagonals are a+b and b+c

Answer 1

D1 = a + b = i - 3j + 2k

D2 = b + c = -i + 2j

Area of parallelogram = 1/2 |D1x D2|
=> 1/2 |(i - 3j + 2k) x (-i + 2j)|
=> 1/2|-4i - 2j - k|
=> √21 / 2