Find a· b.
-$$\mathbf { a } = 10 \mathbf { i } + 6 \mathbf { j } , \quad \mathbf { b } = 5 \mathbf { i } + 3 \mathbf { j }$$
A) $\langle 50,18 \rangle$
B) $- 32$
C) $\langle 15,9 \rangle$
D) 68

Question

Quizplus · Accepted Answer

The dot product of two vectors $\mathbf{a} = a_i\mathbf{i} + a_j\mathbf{j}$ and $\mathbf{b} = b_i\mathbf{i} + b_j\mathbf{j}$ is calculated as $a_i \cdot b_i + a_j \cdot b_j$. For vectors $\mathbf{a} = 10\mathbf{i} + 6\mathbf{j}$ and $\mathbf{b} = 5\mathbf{i} + 3\mathbf{j}$, the dot product is $10 \cdot 5 + 6 \cdot 3 = 50 + 18 = 68$.

Find A· B - a=10i+6j,b=5i+3j\mathbf { a } = 10 \mathbf { i } + 6 \mathbf { j } , \quad \mathbf { b } = 5 \mathbf { i } + 3 \mathbf { j }a=10i+6j,b=5i+3j

Find A· B
- $\mathbf { a } = 10 \mathbf { i } + 6 \mathbf { j } , \quad \mathbf { b } = 5 \mathbf { i } + 3 \mathbf { j }$