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    • Thread Starter

    Hi, I was wondering if someone could help me out with this question please?

    The question is, the area \Delta of a triangle is calculated by using the formuala \Delta = \frac{1}{2} b c \sin A. Use methods of partial differentiation to estimate the maximum error in \Delta when b=25\pm0.1 \ \ \ c=30 \pm 1.5 \ \ \ A=120 \pm 2.

    What I have so far is \delta \Delta \approx ( \frac{1}{2} c \sin A ) \delta b + ( \frac{1}{2} b \sin A ) \delta c + ( \frac{1}{2} b c \cos A ) \delta A

    and since percentage error = \frac{\delta \Delta}{\Delta} \times 100,

    the expression I got for percentage error is

    percentage error  100 \times ( \frac{ \delta b}{b} + \frac{ \delta c}{c} + \frac{ \delta A }{tanA} )

    but whenever I put my values in I don't get the given answer... So far I've tried different things, but keep not getting the given answer :mad: . What am I doing wrong?

    For maximum error do I want \delta b = 0.1 \ \ \ \delta c = 1.5 \ \ \ \ \delta A = 2??

    Thanks in advance

    EDIT: latex mistakes
    • Thread Starter

    Anyone at all? I left this question but now have come back to it and its still bugging me greatly
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Updated: January 16, 2010

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