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## Main Question or Discussion Point

I need some major help with some dot products. I was curious if when getting the dot product, you add the angles of each one to each other. I'll give the problem:

theta=(/)

Find A*B(dot product)

A=8.6i+5j

B=9.7i+2.6j

So i used the formula my teacher gave me to find the angle, theta, tan(/)=y/x. So i got the Angle for each:

tan(/)=5/8.6

(/)=tan^-1(5/8.6)

(/)=30.2

and then for B:

tan(/)=2.6/9.7

(/)=tan^-1(2.6/9.7)

(/)=15

So now, I am given two formulas to get the dot product

A*B=ABcos(/)

AB means the magnitude of A multiplied by the magnitude of B. I can get that, but it asks for one angle... what do I do? Add the two angles together? Or subtract them? I'm confused, please help!

theta=(/)

Find A*B(dot product)

A=8.6i+5j

B=9.7i+2.6j

So i used the formula my teacher gave me to find the angle, theta, tan(/)=y/x. So i got the Angle for each:

tan(/)=5/8.6

(/)=tan^-1(5/8.6)

(/)=30.2

and then for B:

tan(/)=2.6/9.7

(/)=tan^-1(2.6/9.7)

(/)=15

So now, I am given two formulas to get the dot product

A*B=ABcos(/)

AB means the magnitude of A multiplied by the magnitude of B. I can get that, but it asks for one angle... what do I do? Add the two angles together? Or subtract them? I'm confused, please help!