Question

Determine whether the expression make sense mathematically, if not explain why.

a) ||u|| * ||v||
b) (u * v) - w
c) (u * v)-k
d) k * u

Answer 1

sec=1/cos  and cot = cos/sinso, if sec >0 , so theta should be in I or IV quadrant, but you have cot <0,which means that sin should be <0it will leave you with IV quadrant as an answer

Answer 2

||u|| x ||v|| does noot make sence mathematically because you cannot do the cross product of two scalars.

(u x v) - w makes sence mathematically because the cross product of two vectors is a vector from which another vector can be subtracted.

(u x v) - k does not makes sence mathematically because the cross product of two vectors is a vector from which a scalar cannot be subtracted.

k x u does not make sense mathematically because, you cannot have the cross product of a scalar and a vector.