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Should not angle between vector P and Q be 180-θ rather than θ? According to my book it is θ.

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- #1

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Should not angle between vector P and Q be 180-θ rather than θ? According to my book it is θ.

- #2

nasu

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Another way to look at it is that the projection of Q along P is in the positive direction so the angle should be less than 90 degrees.

All this assumes that the vector Q is from A to C. It does not have an arrow in the drawing.

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sophiecentaur

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The parallelogram is just a 'construction'. The vectors are OA and OB, which makes the angle between them θ. Another way of looking at it is to consider the difference between the respective angles of each vector and the X axis (or any other axis).View attachment 100320

Should not angle between vector P and Q be 180-θ rather than θ? According to my book it is θ.