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Math Help - Trigonometric Subtraction

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    Trigonometric Subtraction

    How [6(pi) - 2sin(3pi)]/5 = 1.87?

    I get zero for 2sin(3pi). There is no way the answer is 1.87.

    6(pi)/5 = 1.2, right?
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    Re: Trigonometric Subtraction

    Quote Originally Posted by nycmath View Post
    How [6(pi) - 2sin(3pi)]/5 = 1.87?

    I get zero for 2sin(3pi). There is no way the answer is 1.87.

    6(pi)/5 = 1.2, right?

    calculating in radians I actually get [6*pi]/[5] = 3.77 (double as 1.87) ...
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    Re: Trigonometric Subtraction

    Quote Originally Posted by nycmath View Post
    How [6(pi) - 2sin(3pi)]/5 = 1.87?

    I get zero for 2sin(3pi). There is no way the answer is 1.87.

    6(pi)/5 = 1.2, right?
    This is clearly miswritten. That "6 pi" looks like it should be in a trig function itself. And perhaps that "5" in intended to be inside the sine? I.e. 2 sin(2pi/5)?
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    Re: Trigonometric Subtraction

    I forgot to set my calculator to radians.
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    Re: Trigonometric Subtraction

    Quote Originally Posted by nycmath View Post
    I forgot to set my calculator to radians.
    Given your initial problem statement that won't matter...the only trig function you evaluated you set to 0 (correctly) so radian/degree mode will have no effect. I agree with HallsofIvy: Are you sure your problem is written correctly?

    -Dan
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    Re: Trigonometric Subtraction

    Yes, the problem is written correctly.
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