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integration problem! watch

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    I got an integration question that came in a diff equation yesterday
    They asked to integrate 1/4y
    Now being the idiot i am I put 1/4 Ln4y, which gives the same, but 1/4lny also does.
    Would I be credited?Or would they take off the mark?
    ALso I had to find a value of C etc in the diff eq, and my value was off since i did that, woudl I be credited?
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    ln4y = ln4 + lny , where ln4 is a constant.
    Not sure about the marking though...
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    (Original post by dinesh)
    I got an integration question that came in a diff equation yesterday
    They asked to integrate 1/4y
    Now being the idiot i am I put 1/4 Ln4y, which gives the same, but 1/4lny also does.
    Would I be credited?Or would they take off the mark?
    ALso I had to find a value of C etc in the diff eq, and my value was off since i did that, woudl I be credited?
    INT 1/4y dy = (1/4)INT(4/4y) dy=(1/4)ln(4y)+C [Function and derivative]
    INT 1/4y dy = (1/4)INT(1/y) dy = (1/4)lny+K [Standard integral of 1/y]
    Both (1/4)ln4y+C and (1/4)lny+K are both correct. The second can be written as (1/4)lny+(1/4)ln4+C, which simply shows they are equivelant and there is simply a different constant.
    If you found the correct value of C for the integral you have, giving you the right particular solution, then you would get the mark.
    Also, don't forget you are given marks throughout a question, so even if you were to make a mistake at the very end you would get many of the marks.
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    Thanks
    the first part of the question was separting a partial fratcion and integration
    1 (dividied by ) ( y(4-y)

    So I got one to be 1/4y and integrated as 1/4ln4y
    iT was for 4 marks, so I am hoping I get all 4

    Thanks for the help guys.
 
 
 
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Updated: June 2, 2005

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