Question

Evaluate
(2j−j).(3i+k)
5
6
2
3

Answer 1

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Answer on Question #56012 – Math – Analytical Geometry

Question

Evaluate

$$(2j-j)\cdot(3i+k)$$

5

6

2

3

Solution

The Dot Product can be calculated in the following way:

If $v = ai + bj + ck$ and $w = di + ej + fk$

then

$$v \cdot w = ad + be + cf$$

In our case $v = 0i+j+0k$ and $w = 3i+0j+k$ .

Then $v \cdot w = 0 \cdot 3 + 1 \cdot 0 + 0 \cdot 1 = 0$

Answer: $(2j-j)\cdot(3i+k) = 0$