What is the cross product of #[1,2,1]# and #[3,1,-5] #?
1 Answer
Jan 2, 2016
Explanation:
In general:
#[a_x, a_y, a_z] xx [b_x, b_y, b_z]=[abs((a_y, a_z), (b_y, b_z)), abs((a_z, a_z), (b_z, b_x)), abs((a_x, a_y), (b_x, b_y))]#
So:
#[1,2,1] xx [3,1,-5]#
#= [abs((2, 1),(1,-5)), abs((1, 1), (-5, 3)), abs((1, 2),(3,1))]#
#= [(2*-5)-(1*1), (1*3)-(1*-5), (1*1)-(2*3)]#
#= [-10-1, 3+5, 1-6]#
#= [-11, 8, -5]#
