You are Here: Home

# C4 Formula for calculating area under a curve Tweet

Maths and statistics discussion, revision, exam and homework help.

Announcements Posted on
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
1. C4 Formula for calculating area under a curve
∫y dx/dt

When attempting to calculate the area under a curve. Do you always use the above formula? Or are there exceptions? Because I am sure I learnt a different formula in C2, just can't remember

Thanks
2. Re: C4 Formula for calculating area under a curve
Most often you will need
3. Re: C4 Formula for calculating area under a curve
Not sure if I've grasped what you're asking...
You use the equation of the curve you are integrating. It depends if the equation is or as to whether you use or .
4. Re: C4 Formula for calculating area under a curve
(Original post by BabyMaths)
Most often you will need
HOw do you know whether to apply the above formula, or the one I gave? Thanks
5. Re: C4 Formula for calculating area under a curve
(Original post by sabre2th1)
HOw do you know whether to apply the above formula, or the one I gave? Thanks
I think you meant . This is handy when you have parametric equations.
6. Re: C4 Formula for calculating area under a curve
Given a function f(x), the notation:

Is more or less equivalent to saying: "A is equal to the sum of the values of f(x) over all values of x between b and c"

In other words, A is the area under the curve y = f(x) between the values x = b and x = c.

(EDIT: assuming the curve does not cross the x-axis.)
Last edited by james.h; 20-06-2012 at 13:50. Reason: :ninja:
7. Re: C4 Formula for calculating area under a curve
(Original post by james.h)

Is equivalent to saying: "A is equal to the sum of the values of f(x) over all values of x between b and c"
Kind of a dodgy definition don't you think?
8. Re: C4 Formula for calculating area under a curve
(Original post by BabyMaths)
Kind of a dodgy definition don't you think?
Implicitly assumed here are that the "function" is "nice" (continuous, piecewise finite, &c).

...Okay, fine, but it gets the general idea across.