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5 votes
Find a ⋅ b. a = <2, 4>, b = <2, 5>

2 Answers

5 votes

Answer: The value of a.b = 24.

Explanation:

Since we have given that


\vec{a}=2\hat{i}+4\hat{j}\\\\and\\\\\vec{b}=(2\hat{i}+5\hat{j})

We need to find the dot product of a.b:

As we know that


\hat{i}.\hat{i}=1\\\\and\\\\\hat{j}.\hat{j}=1

So, it becomes,


\vec{a}.\vec{b}=(2\hat{i}+4\hat{j}).(2\hat{i}+5\hat{j})\\\\\vec{a}.\vec{b}=2* 2+4* 5\\\\\vec{a}.\vec{b}=4+20\\\\\vec{a}.\vec{b}=24

Hence, the value of a.b = 24.

User JC Brand
by
8.2k points
5 votes
we have that
a = <2, 4>-------> 2i+4j
b = <2, 5>------> 2i+5j

a.b-------> 2*2+4*5--------> 24

the answer is 24
User Babybear
by
8.5k points

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