Respuesta :
Answer:
[tex]a\cdot b[/tex] = 1
Step-by-step explanation:
Given that,
Vector [tex]a=5i+7j[/tex]
Vector [tex]b=-4i+3j[/tex]
We need to find [tex]a{\cdot} b[/tex] means the dot product of a and b. So,
[tex]a{\cdot} b=(5i+7j){\cdot} (-4i+3j)[/tex]
We know that,
[tex]i{\cdot}i, j{\cdot}j,k{\cdot}k=1\ \text{and}\ i{\cdot}j= j\cdot i=0[/tex]
So,
[tex]a{\cdot} b=(5i+7j){\cdot} (-4i+3j)\\\\=5i{\cdot}(-4i)+5i{\cdot} 3j+7j\cdot(-4i)+7j\cdot 3j\\\\=-20+21\\\\=1[/tex]
So, the value of [tex]a\cdot b[/tex] is 1.
