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Thread: *EDIT* - Solved

  1. Mar 19th, 2003, 08:31 PM #1
    boscord
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    Unhappy *EDIT* - Solved

    God help me...er...you, please.

    I need to find out how to solve

    (11 * pi) / 8

    without using a calculator, and getting the exact value, only knowing the addition, subtraction, double, squares, and half-angle identities, as well as the basic chart for angles 0, 30, 45, 60, and 90 degrees, for all six major trigonometric function.

    Please help and please show work, my life depends on it!

    THANK YOU mucho in advance!

    -Rob DiMarco
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    Edit: Well, oops! I did mean sin (11pi/8) but I got it already, thanks anyways!
    Last edited by boscord; Mar 20th, 2003 at 04:18 PM.
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  2. Mar 19th, 2003, 11:39 PM #2
    bugzpodder
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    do you mean sin(11pi/8) cos(11pi/8) ?? 11pi/8 by iteself is just an angle and it is already in simplest form
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  3. Mar 20th, 2003, 11:44 PM #3
    prog_tom
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    By using the sum and difference formula:

    sin(11pi/8) also = sin (4pi/8 + 7pi/8) = sin(pi/2) * cos (22.5deg) + cos (pi/2) * sin (22.5deg).

    Now figuring out the sines and cosines at 22.5deg could be a real hassle, if you want the EXACT VALUE.

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