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projectiles question

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  • 31-03-2007 6:16pm
    #1
    Shox
    Closed Accounts Posts: 78 ✭✭


    could someone let me know how you get the 2 statements above from this diagram


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    #2
    ZorbaTehZ
    Registered Users Posts: 2,149 ✭✭✭ZorbaTehZ


    Maths Tables page 9,
    Cos(A+B) rule and the Sin(A+B) rule i believe.


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    #3
    cocoa
    Registered Users Posts: 1,269 ✭✭✭cocoa


    well, using the formulae might work, but what seems easier (to me anyway) is to draw in a right angled triangle with angles 2B, 90-2B and 90. then it becomes clear (if you mark which side is hypoteneuse) that the sin of one angle is the cos of another.


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    #4
    Delphi91
    Registered Users Posts: 1,501 ✭✭✭Delphi91


    The other way that I would look at it is that where two angles make up 90 degrees, the cos of one is equal to the sin of the other.

    E.g. cos 30 = sin 60, sin 10 = cos 80, etc, etc.


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