$\"\"$

Therom 3 :

If $\"\"$ is the angle between vectors $\"\"$ and $\"\"$ then $\"\"$ .

$\"\"$

Cauchy-Schwarz Inequality is $\"\"$ .

The value of $\"\"$ lies between $\"\"$ and $\"\"$ .

$\"\"$ .

From the above inequality we will get the desired solution, by noticing that we can write the

statement in the form of $\"\"$ .

$\"\"$ .

$\"\"$

Cauchy-Schwarz Inequality $\"\"$ is proved.