(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Leta theta be the angle between the vectors u=2i +3j -6k and v=2i + 3j+6k

A) use the dot product to find cos theta

b) use the cross product to find sin theta

c) confirm that sin^2(theta) + cos^2(theta)=1

3. The attempt at a solution

I got a to be 117 degrees, but however b and c are stumping me, whenever I try to do b I get an the cross product and then try to solve for theta but i get an error using my calculator, I rechecked my calculations twice and everything make sense am I doing something wrong or is it really not possible.

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# Use the cross product to find the sin of an angle then prove it

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