What is the angle between these two vectors?

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SUMMARY

The angle between vectors A and B, given their scalar product of -4.00 and a vector product magnitude of 9.00, is 114 degrees. The calculations involved using the relationships ABcos(θ) = -4 and ABsin(θ) = 9, leading to the tangent of the angle being -2.25. The initial calculation of -66 degrees was incorrect due to the misunderstanding that angles cannot be negative. The correct angle is derived by adjusting to the second quadrant, resulting in 180 - 66 = 114 degrees.

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Vectors A and B have scalar product -4.00 and their vector product has magnitude 9.00.

Here's what I did:

ABcos=-4
ABsin=9

sin/cos=-2.25

tan=-2.25

angle=-66?

I entered this and it says it's incorrect. What did I do wrong?
 
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Pay attention that the angle between two vectors won't be negative ...

There should be an angle that its cos is - and its sin is +

angle: 180 - 66 = 114 degree
 

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