find the following cross products.

Question

If a=⟨1,2,1⟩ and b=⟨5,11,1⟩, find the following cross products.

1. a×b=

2. b×a=

Answer 1

Compute using the formula for a cross product.

a x b= [(2·1)-(1·11) , (1⋅5)-(1⋅1), (1⋅11)-(2⋅5)] = 〈 -9 , 4 , 1 〉

b x a = [ (11⋅1) - (1⋅2) , (1⋅1)- (5⋅1) , (5⋅2)- (11⋅1)] = 〈 9 , -4 , -1〉