- #1

Cacophony

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## Homework Statement

a) d^2/(dx^2): ln(x+1)

b) d^3/(dx^3): x^7 + 4x^6 - x^2

c) d^2/(dx^2): 1/(x + 1)

d) d^4/(dx^4): cos(2x)

## Homework Equations

none

## The Attempt at a Solution

Can someone tell me if these are right?

a)= -(1/(x + 1)^2)

b)=210x^4 + 480x^3

c)= (2/(x + 1)^3)

d)= 16cos(2x)