sand dollar. n. 1. Any of various thin circular echinoderms of the order Clypeasteroida, especially Echinarachnius parma, of coastal northern Atlantic and Pacific waters, having a covering of short movable spines.
One reason why linear algebra is very useful is that linear transforms of normal variables are normal. If x ~ N(a, A), then Bx+b ~ N(Ba+b, BABT). In a way, when everything is linear and normal, everything is nice and analytically tractable.
Elementary algebra is the branch of math that substitutes letters for unknown numbers in an equation and manipulates them to determine a solution. Elementary algebra is the branch of math that substitutes letters for unknown numbers in an equation and manipulates them to determine a solution. Algebra: Using Mathematical Symbols Search the site GO