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    I require some help with an integration question. Area between a line and a curve. I have attached the question and my working. I get an answer of 21/2 and the book says the answer is 15. I believe it’s the book that is wrong but would just like to be sure if anyone could help that would be great.
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    Here is the question and working.
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    (Original post by Mortifiedpenguin)
    Here is the question and working.
    i believe you need to use the x coordinate limits 4 and -5, rather than the y coordinates
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    The area under the x-axis is negative. You should integrate the area above and then below (this one will be negative, so take the sign into account) and add up the areas.
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    (Original post by Mortifiedpenguin)
    Here is the question and working.
    Unless I've officially lost the plot (the chance of such is quite high), that cannot be the graph for y=x^2+4x
    Wrong shape and co-ordinates I think
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    scrap my last comment!! i think your original equation to integrate should be: x^2+x-2
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    Actually yeah that graph is ********. There's no way x^2+4x makes that graph.
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    ah yes.. that graph looks to be y=-x^2+4 !
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    you can make a triangle
    find the area of the triangle and take away from the area under the curve
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    I have tried changing the equation to -x^2 + 4x that didn’t work either that gives 9/2 from what I can recall. I think the graph is wrong also. And I am using the x coordinates 😁
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    Maybe this is an impossible one.

    I was playing around with my calculator because of this question and got a 19/2. Averaging them out gives a 15 but I don't see why that would be done.

    On a serious note, something is very wrong with that question
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    It’s just wrong. The equation is wrong, the answer, based on the equation given is wrong. The book is so **** it’s unreal, full of wrong answers and mistakes in questions. Especially in the calculus section.
 
 
 
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Updated: November 6, 2017
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