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Integration question

http://www.ocr.org.uk/Images/61388-question-paper-unit-4722-01-core-mathematics-2.pdf

Question 4

I got for the first part 22(4/5)

What does this value represent I thought it represents the shaded region but it does not?
(edited 11 years ago)
Original post by IShouldBeRevising_
http://www.ocr.org.uk/Images/61388-question-paper-unit-4722-01-core-mathematics-2.pdf

Question 4

I got he first part the 22(4/5)

What does this value represent I thought it represents the shaded region but it does not?


You need the area under the line (the shape is a rectangle) minus the area under the curve :smile:
Reply 2
Avatar for davros
davros
16
Original post by IShouldBeRevising_
http://www.ocr.org.uk/Images/61388-question-paper-unit-4722-01-core-mathematics-2.pdf

Question 4

I got he first part the 22(4/5)

What does this value represent I thought it represents the shaded region but it does not?


Depends what you evaluated! integration usually gives you the area underneath a curve - typically between a curve and the x-axis. You may need to subtract the area you've found from the area of a rectangle to get the area of the shaded part.
Original post by Indeterminate
You need the area under the line (the shape is a rectangle) minus the area under the curve :smile:



Original post by davros
Depends what you evaluated! integration usually gives you the area underneath a curve - typically between a curve and the x-axis. You may need to subtract the area you've found from the area of a rectangle to get the area of the shaded part.


I did the exact thing in the mark scheme but did not subtract my answer form the area of the rectangle... I thought the work I did gave the area of the shaded region?

Here is the mark scheme

http://www.ocr.org.uk/Images/59336-mark-scheme-january.pdf
Reply 4
Avatar for gaffer dean
gaffer dean
Original post by IShouldBeRevising_
http://www.ocr.org.uk/Images/61388-question-paper-unit-4722-01-core-mathematics-2.pdf

Question 4

I got for the first part 22(4/5)

What does this value represent I thought it represents the shaded region but it does not?

Unparseable latex formula:

\int^2_-_2 x^4+3\ dx

will give you the area underneath the curve.
Then work out the Area of rectangle which is 4∗19=764*19=76 and subtract this to get the required area.

(sorry, limits were supposed to be -2 and 2)
(edited 11 years ago)
Original post by gaffer dean
Unparseable latex formula:

\int^2_-_2 x^4+3\ dx

will give you the area underneath the curve.
Then work out the Area of rectangle which is 4∗19=764*19=76 and subtract this to get the required area.


Oh right yes thank you.. I thought integration gave you the area of the shaded region.
Reply 6
Avatar for gaffer dean
gaffer dean
Original post by IShouldBeRevising_
Oh right yes thank you.. I thought integration gave you the area of the shaded region.

you're welcome, read section 11.2 in the book if you still don't understand.
BTW, limits were supposed to be -2 and 2.
(edited 11 years ago)

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