Question

find | a | and |b| ,if |a|= 2|b| and (a +b) (a-b) = 12 ​

Answer 1

Answer:

Step-by-step explanation:

|A|=2  

|B|=5  

|A×B|=8  

We know that ,

|A×B|=|A||B|sinθ  

So,  2×5×sinθ=8  

⟹sinθ=45  

⟹cosθ=35  

To evaluate:

A⋅B=|A||B|cosθ  

⟹A⋅B=2×5×35  

⟹A⋅B=6