For three vectors a → ,   b → and c → , if | a → | = 2 ,   | b → | = 1 ,   a → × b → = c → and b → × c → = a → , then the value of a → + b →     b → + c →     c → + a → is equal to

Step-by-step solution

We know that, a → + b →     b → + c →     c → + a → = 2 [ a →   b →   c → ] Given b → × c → = a → Taking dot product with a → , we get, a →   b →   c → = a → . a → = a → 2 = 4 Hence, a → + b →     b → + c →     c → + a → = 2 × 4 = 8