How do I find the cross product of #<-13, 4># and #<-56, 0>#?

1 Answer
Jan 23, 2015

You have two options to evaluate the cross product:
1) the cross product of two vectors #vecv# and #vecw# is a vector with modulus equal to#|vecv|×|vecw|×sin(theta)# (#theta# is the angle between the vectors), direction perpendicular to the plane formed by the two vectors and oriented using the "thumb of the right hand" rule;
2) evaluate the determinant:
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In your case I would use the second option and use the first to check the result. So:
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So basically, the result is a vector in the positive #z# direction and modulus 224, or:
#<0,0,224>#

Using the first approach you get the same result considering:
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Try to evaluate the modulus (using #|vecv|×|vecw|×sin(theta)#) and consider the direction of the resulting vector you'll see that it matches.