If a4+a2b2+b4=3 and a2+ab+b2=3, what is the value of a2+b2?

A 4

B 6

C 3

D 2

Solution

Correct Answer: Option D

দেওয়া আছে, a4+a2b2+b4=3 .........(i) 
  এবং a2+ab+b2=3 .............(ii) 
 
 এখন, (i) নং হতে পাই, a4+a2b2+b4=3 
⇒ (a2)2  + 2a2b2  + (b2)2  - a2b2  = 3  
⇒  (a2 + b2 )2 - a2b2  = 3 
⇒  (a2 + b2 )2  - (ab)2  = 3 
⇒  (a2 + b2 + ab) (a2 + b2 - ab)  = 3 
⇒  3.(a2 + b2 - ab)  = 3 [From 2]
⇒  a2 + b2 - ab = 1 -----(3)

From (2) + (3),
2 (a2 + b2)=4
∴ a2 + b2=2

Practice More Questions on Our App!

Download our app for free and access thousands of MCQ questions with detailed solutions