1. Let f(x) = 1/(1+x) for x ¹ -1. What is the nth derivative, f(n)(x)?

 

A. n!(1+x)n+1

B. –n!/(1+x)n+1

C. n!/(1+x)n+1

D. –n!/(1+x)n

E. (-1)nn!/(1+x)n+1

 

 

Solution: The answer is E

 

To find the nth derivative of f(x), take a few consecutive derivatives starting with the first and try to recognize a pattern as follows,