If C (dot) C= IC^2I how can I prove cosine law with vectors?
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Originally Posted by Clairvoyantski If C (dot) C= IC^2I how can I prove cosine law with vectors? Use this property:
where is the angle between and .
Form a triangle with and as two of its sides. The remaining side is represented by . Squaring the length of this side gives
Now just finish it up.
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