O A B C is a tetrahedron. If D , E are the midpoints of O A and B C respectively, then D E → =

Step-by-step solution

It is given that O A B C tetrahedron. And, D is the mid-pont O A → and E → mid-point od B C → ​​​​​​​ So, let O A → = a → O B → = b → O C → = c → Since, D is the mid-point of O A → , therefore D → = a → 2 O E → = b → + c → 2 Now, D E → = O E → - O D → ⇒ D E → = b → + c → 2 - a → 2 ⇒ D E → = - a → + b → + c → 2 ⇒ D E → = 1 2 - O A → + O B → + O C →