When is it necessary to add "+c" when antidifferentiating?

[atar90please]

Whilst studying antidifferentiation i noticed that +c was not always included on the end of the equation. Why is this?

MOD EDIT: Changed to a more informative title - 2/cos(c)

[alondouek]

The question may have asked for "an" antiderivative. In this case, the +c is left off because +c essentially covers every possible constant added to that antiderivative, though only one is required by the question.

[atar90please]

Ok thank you

[Zealous]

Could marks be lost if you add a +c to a question asking for "an" antiderivative? Just being pedantic =p

[availn]

Could marks be lost if you add a +c to a question asking for "an" antiderivative? Just being pedantic =p

From what I hear, no. Because even with the +c it is still "an" antiderivative. The +c just becomes optional when it goes from from "the" to "an", but everyone says to put in the +c anyways.

[Phy124]

Also just a reminder that whenever you guys find the general antiderivative of a function and add to the end, ensure that you write something like "" or "for any constant "

[b^3]

When it says "find an anti-derivative" you don't have to add the . Technically you shouldn't, as you'd be given a family of curves, rather than a single curve (although I guess giving many counts as giving 'an' anti-derivative).

With that being said, in cases where it does say, as above, "find an anti-derivative", VCAA accepts both.
For example, Q2 on the 2012 Methods Exam 1.

Question 2
Find an anti-derivative of with respect to .

http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2012/2012mmcas1-w.pdf

The assesors report gives this.

When is any real number, may be omitted.

http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2012/mm1_assessrep12.pdf

In other cases you'll need to add the .

Although, for sacs and such it will depend on your teacher/who marks it.