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.
Algebra is important for future employment opportunities in Californiaâs increasingly knowledge-based economy, even in jobs con-sidered to be âblue collar.â For example, an applicant must have passed Algebra I to enter an electrician apprenticeship program. But if students are aiming for college, algebra is essential.