What is the cross product of #[9,4,-1]# and #[-1, -1, 2] #?

1 Answer
Feb 10, 2016

Answer:

#A X B=7i-17j-5k#

Explanation:

#A=[a_i,a_j,a_k]#
#B=[b_i,b_j,b_k]#
#A X B=i(a_j*b_k-a_k*b_j)-j(a_i*b_k-a_k*b_i)+k(a_i*b_j-a_j*b_i)#
#thus;#
#A=[9,4,-1]#
#B=[-1,-1,2]#
#A X B=i(4*2-(-1*-1))-j(9*2-(-1*-1))+k(-1*9-4*-1)#
#A X B=i(8-1)-j(18-1)+k(-9+4)#
#A X B=7i-17j-5k#