Answer
$-4$
Work Step by Step
Our aims is to compute the dot product , for this we will multiply the corresponding components together and then add.
In general, we have the formula as: $ \lt a , b\gt \cdot \lt c, d \gt =ac+bd$
Therefore,
$ \lt 2, 4 \gt \cdot \lt 0, -1 \gt = (2)(0)+(4)(-1)=0-4=-4$
