# [✓] Simplify 1.w? (w is any vector)

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 How to simplify 1.w? w is any vector example: {1, 2, 3} 1 is a scalar, result of 1.w is 1.{1, 2, 3} I want it to be {1, 2, 3}
10 months ago
2 Replies
 Sander Huisman 1 Vote . refers to the contraction (dot product) of two general tensors (array, list, matrix, vector). For example: a.b This will contract the last index of a with the first index of b. Scalar multiplication, what you want, can be written in (at least) 3 ways: 1{1,2,3} 1*{1,2,3} Times[1,{1,2,3}] 
10 months ago
 Robert Hanlon 1 Vote w = {1, 2, 3}; 1. is an approximate real number. Multiplying an approximate real number times a list or array of exact numbers will produce a list or array of approximate real numbers. 1. w (* {1., 2., 3.} *) If you want exact numbers, use Rationalize 1. w // Rationalize (* {1, 2, 3} *)