Hello,

I didn't get the whole problem oO

But the antiderivate of is easy to find.

An antiderivative of is

Here,

So

As you've calculated, an antiderivative will be

What do you mean by proportional ? You have a function equal to :

with a a constant ?

If so, it's ok, the antiderivative doesn't take care of the constants...

An antiderivative of f will be a*[antiderivative of 1/(10+x)^2]