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Math Help - pls help my problem

  1. #1
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    pls help my problem

    give me the solution from the top of a building the angle of depression of a point on the same horizontal plane with the base of the building is observed to be 60 degree what will be the angle of depression of the same point when viewed from a position one third of the way up the building
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  2. #2
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    If you draw a sketch, look at some ratios, you will find a nice relationship between the two angles of depression.
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  3. #3
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    Re: pls help my problem

    can u give a formula for my problem
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  4. #4
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    Did you draw a sketch of the resulting triangles? Trigonometry frequently involves drawing diagrams and looking for similar triangles, etc.
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  5. #5
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    Re: pls help my problem

    can u give me the answer
    for me
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  6. #6
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    No, I'm not going to simply give you the answer. I will help you figure out how to do the problem...if you are willing to show some effort.

    Put pen/pencil to paper, and draw a sketch. Tell us what you find, and we will be glad to help.
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  7. #7
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    Re: pls help my problem

    ok sir the triangle are two how can i find the formula can u help me pls
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  8. #8
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    Okay, I assume you have labeled the distances and angles...

    Using trigonometry, what is the ratio of the horizontal distance to the point to the height of the building?

    Hint: use the tangent function. Do you see why?

    edit: Or use the special angles within the larger triangle.
    Last edited by MarkFL; September 24th 2012 at 11:09 PM.
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  9. #9
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    Re: pls help my problem

    y can i use tangent funtion?
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  10. #10
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    Re: pls help my problem

    tan 60 degree is 10.23856
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  11. #11
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    No, \tan(60^{\circ})=\sqrt{3}.

    The reason the tangent function is useful here, is that it relates an angle in a right triangle to the ratio of the opposite to the adjacent side.

    \tan\theta=\frac{\text{opposite}}{\text{adjacent}}

    If \theta=60^{\circ}, what do the opposite and adjacent sides of the larger triangle represent?
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  12. #12
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    Re: pls help my problem

    0.57735
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  13. #13
    MHF Contributor MarkFL's Avatar
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    Re: pls help my problem

    I have no idea where you got that number from, but there is no need for decimal equivalents.

    In your diagram, what is the side that is opposite the 60 angle?
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