Mathematics

Problem

Which of the following equals the magnitude of

k\mathbf{a}

when

\mathbf{a}

is a non-zero vector and

k

is any real scalar? a)

k|\mathbf{a}|

|k|+|\mathbf{a}|

|k|\,|\mathbf{a}|

|k|\,|\mathbf{a}|^{2}