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Motion In A Plane

Question
CBSEENPH11018278

Define dot product. Show that dot product of two vectors follows commutative law.

Solution

Dot product of two vectors is defined as the product of their magnitudes and cosine of the angle between them. 
                straight A with rightwards arrow on top. straight B with rightwards arrow on top space equals space AB space cos space straight theta 
Now         straight A with rightwards arrow on top. straight B with rightwards arrow on top space equals space AB space cosθ 
                      equals BAcosθ space equals space straight B with rightwards arrow on top. straight A with rightwards arrow on top 
Hence, dot product of two vectors is commutative in nature.