Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Vectors

Question:

The scalar of $\vec A.\{(\vec B + \vec C) × (\vec A + \vec B + \vec C)\}$ equals :

Options:

0

$[\vec { A } \vec { B } \vec { C } ]+[\vec { B } \vec { C } \vec { A } ]$

$[\vec { A } \vec { B } \vec { C } ]$

none of these

Correct Answer:

0

Explanation:

$(\vec B+\vec C)×(\vec A+\vec B+\vec C)=\vec B×\vec A+\vec B×\vec C+\vec C×\vec A+\vec C×\vec B=\vec B×\vec A+\vec C×\vec A$

$⇒\vec A.\{(\vec B + \vec C) × (\vec A + \vec B + \vec C)\}=\vec A.(\vec B×\vec A+\vec C×\vec A)=0$

Hence (A) is the correct answer.