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匿名
匿名 發問於 科學及數學數學 · 4 月前

Maths problem, urgent!!! thanks a lot.?

Proof why the shadow area is

wb-((b^2+2ab)/2)*tan(θ).

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1 個解答

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  • 匿名
    4 月前
    最愛解答

    Question:

    Prove the shadow area = wb - [(b² + 2ab)/2] tanθ.

    https://s.yimg.com/tr/i/36403e0ae04448ef951f340aa5...

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    Solution:

    The shadow area

    = Area of the parallelogram BDFG - Area of the trapezium BDEC

    = wb - ( Area of ΔADE - Area of ΔABC )

    = wb - [ (a + b)(a + b) tanθ / 2 - (a)(a) tanθ / 2 ]

    = wb - [(a + b)² - a²] tanθ / 2

    = wb - [(b² + 2ab)/2] tanθ

    Attachment image
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