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Integration: ares under two curves watch

1. Did an exam recently with a question like the title says.

Used the ( integral of y1 - y2 ) dx rule, however, I integrated fully before working out y1 - y2. However, someone else smarter than me worked out y1-y2 before integrating.

Does that affect the overall answer or are the steps interchangeable?
2. (Original post by Regret786)
Did an exam recently with a question like the title says.

Used the ( integral of y1 - y2 ) dx rule, however, I integrated fully before working out y1 - y2. However, someone else smarter than me worked out y1-y2 before integrating.

Does that affect the overall answer or are the steps interchangeable?
Can you post an example of what you mean?
3. Integrating before subtracting is just taking the area under y2 away from the area under y1.

Subtracting before integrating gives you a different function, but the area under that curve is equivalent to the difference above.

In other words, yes, they're interchangeable.
4. I am curious too
5. (Original post by notnek)
Can you post an example of what you mean?
(Original post by TeeEm)
I am curious too
http://qualifications.pearson.com/co...-June-2014.pdf

Question 7C. This isn't the exact question since the exam was on Fridays. The link is volume instead of curve.
6. (Original post by Regret786)
http://qualifications.pearson.com/co...-June-2014.pdf

Question 7C. This isn't the exact question since the exam was on Fridays. The link is volume instead of curve.
in general for continuous .

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