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Math Help - What is a trig function?

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    What is a trig function?

    I dont know if this counts as philosophy, but I already understand how to do trigonometry. I was just wandering, if someone asked me what sin(x) means, what would I say?

    Its the ratio of two certain sides of a right triangle, o and a?
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  2. #2
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    Re: What is a trig function?

    My ancient greek is a bit rusty, but I believe that "sine" means "perpendicular".

    If you drew a unit circle and drew in the radius, an angle is formed with the positive x axis. If you then drew in a line segment from the edge of the radius on the circumference to the x-axis, then this length is the sine of the angle, because it's perpendicular to the x axis.
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    Re: What is a trig function?

    So, it's the length of the side opposite theta, as a function of theta?

    If I had a unit circle, made a triangle with a 45 degree angle, the length of the side opposite that angle would be sin(45)?
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    Re: What is a trig function?

    Correct.
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    Re: What is a trig function?

    Being a function, it relates two sets - in this case a set of numbers taken to be the angle and a set of numbers taken to be the ratio of o and a. For sin(x), you can answer with this interpretation: the function relates the angle x (for any real 'x'), formed by the radius and the x-axis, to a ratio (the ratio is as Prove It and you have already noted).
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    Re: What is a trig function?

    Just bumping this over the spam
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