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    Hi there I was doing this question on eulers step by step method but I got a different answer to the book:

    a curve satifies the differential equation dy/dx = 1/(x^2+16)^1/2

    Starting at the point (3, 2.4) on the curve use a step by step method with a step length of 0.25 to estimate the value of y at x = 3.75, giving your answer to two decimal places.

    My working:

    y(3) = 2.4
    y(3.25) = 2.4+ 0.25(dy/dx)3 = 2.45
    y(3.50) = 2.45+ 0.25(dy/dx)3.25 = 833+ 4root17 / 340
    y(3.75) = 833+ 4root17 / 340 + 0.25(dy/dx)3.50 = 2.5455.. = 2.55 to 2dp.
    But the answer in the book is 2.51.

    Please help, thanks

    Doing this in my head, late at night, I get the same answer as you...
    (though your working is nigh on incomprehensible to me-simplify your fractions! :P )
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Updated: April 13, 2011
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