Question

What is the length (magnitude) of the vector (2,-1)? O A. 1 B. -2 O C. 2 D. D. 5

Answer 1

We are given the following vector

`v=(2,-1)`

The magnitude of a 2-dimensional vector is given by

`|v|=√(x^2+y^2)`

Substitute the given points into the above formula

`\begin{gathered} |v|=√((2)^2+(-1)^2) \\ |v|=√(4+1) \\ |v|=√(5) \end{gathered}`

Therefore, the magnitude of the vector (2, -1) is √5

`|v|=√(5)`