# Finding the Direction Cosines

Okay I have been racking my brain with this one for over a week and still have no clue how to do this.I need to study this for a test I am having and can't seem to figure this out

Consider an arbitrary 3D vector: A=Axx+Ayy+Azz

a) Determine the direction cosines for this vector. These are cos[], cos[] and cos [], where  is the angle between A and x , where  is the angle between A and y, and  is the angle of A and z.

b) Show that the direction cosines obey the relationship (cos[])2+(cos[])2+(cos [])2.

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Consider an arbitrary 3D vector: A=Axx+Ayy+Azz

a) Determine the direction cosines for this vector. These are cos[], cos[] and cos [], ...

#### Solution Summary

The expert finds the direction cosines for vectors. The direction cosines obey in relationships are given.