Problem 9

Problem – 9

What is the coefficient of  in ?

 

Solution:

Binomial theorem for (x+y)ⁿ = ⁿC₀xⁿy⁰ + ⁿC₁x^n-1y¹+ ⁿC₂x^n-2y² + ⁿC₃x^n-3y³ +…………+ ⁿC_n-1x¹y^n-1+ ⁿC_nx⁰yⁿ

Using the Binomial theorem, coefficient of x¹⁰ = ¹⁵C₁₀(3)⁵=3003×243 =729729