How do you find the indefinite integral of #int (3/x)dx#?

1 Answer
Nov 11, 2016

# int(3/x)dx=3lnx +C = ln(Ax^3) #

Explanation:

You should remember a standard special case:

# d/dxlnx = 1/x <=> int 1/xdx = lnx + C #

Hence, # int(3/x)dx=3lnx +C #

NB If we write #C=lnA# we can also write the solution as

# int(3/x)dx=3lnx + lnA #
# :. int(3/x)dx=lnx^3 + lnA #
# :. int(3/x)dx=ln(Ax^3) #