যদি a + b = \(\sqrt 5 \) এবং a - b = \(\sqrt 3 \) হয়, তবে a2 + b2 = কত ?

যদি a + b = \(\sqrt 5 \) এবং a - b = \(\sqrt 3 \) হয়, তবে a² + b²= কত ?

A 4

B 8

C 6

D 49

Correct Answer: Option A

a² + b² = \(\frac{{(a + b)+ (a - b)}}{2}\)

\(\frac{{(\sqrt {5)} + (\sqrt {3)} }}{2}\) = \(\frac{{5 + 3}}{2}\) = \(\frac{8}{2}\) = 4