Question

There are two vectors à and b, with an angle between them. Then the dot product of them is A. a. b = ab cos B. a b = (a + b) cos C. a. b = ab sino D.. b = (a + b) sino

Answer 1

Answer:

$a.b=|a||b|\ cos\theta$                                                                    

Explanation:

Let a and b are two vectors such that $\theta$ is the angle between them. Dot product is also known as scalar product.  It is used to find the angle between two vectors such that,

$a.b=|a||b|\ cos\theta$

$\theta$ is the angle between a and b. It can be calculated as :

$\theta=cos^{-1}(\dfrac{a.b}{|a||b|})$

$|a|\ and\ |b|$ are the magnitude of vectors a and b such that :

$|a|=\sqrt{x^2+y^2+z^2}$ if a = xi +yj +zk

and

$|b|=\sqrt{p^2+q^2+r^2}$ if a = pi +qj +rk            

So, the correct option is (a). Hence, this is the required solution.