Question

Find a ⋅ b. a = <2, 4>, b = <2, 5>

Answer 1

We have that
a = <2, 4>-------> 2i+4j
b = <2, 5>------> 2i+5j

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

the answer is 24

Answer 2

Answer: The value of a.b = 24.

Step-by-step 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,

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

Hence, the value of a.b = 24.