Taylor Series?

Question

Represent the function 5ln(9-x) as a power series.

C0 =
C1=
C2 =
C3 =
C4 =
Find the radius of convergence R =

Answer 1

f(x) = f(0)+f´(0)*x+f´´(0)/2!*x^2+f´´´(0)/3!*x^3 +f´´´´(0)/4! *x^4
C0=5 ln 9
C1= -5/9
C2=5/(9^2*2!)
C3= -10/(9^3*3!)
C4=5*2*3/(9^4*4!)

Cn =5 (2*3*4****(n-1)/(9^n*n!)
Cn+1/Cn= = n/9*1(n+1) ===1/9 so r=9