Final answer:
The product of vectors a and b is not defined because they have different lengths.
Step-by-step explanation:
To find the product of vectors a and b, we use the concept of dot product. The dot product of two vectors is the sum of the products of their corresponding components. However, the given vectors a and b have different lengths, so their product is not defined. In order to find a valid product, the vectors need to have the same length. Therefore, the product of a and b in this case is not defined.