Vector Fields in Maple. A vector field is described by a function that takes each point of the plane to a vector. > with(linalg): > F := (x,y) -> [-y,x]; We can evaluate this function at a point by plugging in values for x and y , just like we do with functions whose values are scalars.
The survey of U.S. parents finds that out of children participating in Fall and Winter sports, just 60 percent are wearing mouth guards. Taking a closer look at mouth guard usage for some higher-impact sports, the survey shows that for football, just 32 percent of parents report their child wears a mouth guard, for field hockey, just 14 percent. Lacrosse and ice hockey both fall at 11 percent, alongside volleyball. The complete list can be found here.
Mouth-formed guards are priced at approximately $2 to $30 and also are available at sporting goods and drug stores. Custom-fitted mouth guards cost between $190 and $500 and are available from a dentist.