Question

Calculate the dot product of D and E, where D=7i - 3j + 2k and E=4i + 5j - 3k.

Answer 1

We can calculate the dot product as follows:

$$\vec{D}\cdot\vec{E}=D_x\cdot E_x+D_y\cdot E_y+D_z\cdot E_z,$$ $$\vec{D}\cdot\vec{E}=7\cdot 4+(-3)\cdot 5+2\cdot (-3)=7.$$

Answer:

$\vec{D}\cdot\vec{E}=7$.