Find the cross product of the following vectors. Then use the cross product to find the angle between them.

a = 3i − 2j + 5k and b = 7i + 4j − 8k

Guest Jun 14, 2014

#3**+5 **

I used u and v as general vectors. a and b are your specific vectors. That is they are specific examples of u and v. But if you prefer to think of it as turning a and b into u and v ok! Whatever works for you!

In fact, why don't you rewrite my u and v in terms of a and b (including their components - so u1 becomes a1 etc.)?

Alan
Jun 14, 2014

#6**0 **

sorry, think i did something wrong..my a × b= -4,11,4.

so i'll call it y. y= a3 b1 - a1 b3.

a = 3 − 2 + 5 and b = 7 + 4 − 8

y=(5)(7)-(3)(8)

= 35-24

=11

I noticed however you got 59..where did i go wrong?

Guest Jun 14, 2014

#7**0 **

nevermind. i figured it out. two negatives is a positive. Thanks again for the help.

Guest Jun 14, 2014