Dot product of $$$\left\langle -2, 5, -1\right\rangle$$$ and $$$\left\langle -10, 7, -1\right\rangle$$$
Your Input
Calculate $$$\left\langle -2, 5, -1\right\rangle\cdot \left\langle -10, 7, -1\right\rangle$$$.
Solution
The dot product is given by $$$\mathbf{\vec{u}}\cdot \mathbf{\vec{v}} = \sum_{i=1}^{n} u_{i} v_{i}$$$.
Thus, what we need to do is multiply the corresponding coordinates and then add up the results: $$$\left\langle -2, 5, -1\right\rangle\cdot \left\langle -10, 7, -1\right\rangle = \left(-2\right)\cdot \left(-10\right) + \left(5\right)\cdot \left(7\right) + \left(-1\right)\cdot \left(-1\right) = 56.$$$
Answer
$$$\left\langle -2, 5, -1\right\rangle\cdot \left\langle -10, 7, -1\right\rangle = 56$$$A