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Homework Help: Nullspace Question

  1. Nov 23, 2009 #1
    Does anyone know how to approach this problem?

    Let A be an m×n matrix of rank m, where m<n. Pick a point x in R^n, and let x∗ be the point in the nullspace of A closest to x. Write a formula for x∗ in terms of x and A.

    What exactly is the significance of the point x* in the nullspace of A?
  2. jcsd
  3. Nov 23, 2009 #2
    i think this question has something to do with the orthogonality of subspaces and is analogous to saying the shortest distance between a point and an axis is just a perpendicular line...
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