What is the antiderivative of #2/x#?

1 Answer
Mar 26, 2016

#2lnabs(x)+C#

Explanation:

Begin by writing the problem in mathspeak:
#int2/xdx#

We know that #int1/xdx=lnabs(x)+C#; so how can we simplify #int2/xdx# to #int1/xdx#? Well, there's a rule for integrals that says: #intcxdx=cintxdx#; in other words, we can pull constants out of the integral. Because #2# is a constant, we can bring it out:
#=2int1/xdx#

And applying the antiderivative of #1/x#, we have:
#2(lnabs(x)+C)=2lnabs(x)+C->#(note that #2C# is just another constant, so we can write it as #C#)