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Sine Waves...Sine Angles 
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#1
Mar1414, 04:04 PM

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Hello everyone. Can someone explain the relationship between the idea of a sine wave, and the idea of a sine angle? I'm getting into trig, and I hear both terms of sin tossed around, but they seem to be completely unrelated. What does the angle of the triangle have to do with a wave?
Same goes for sin, cos, tan, I know these are ratio's for angles on a right triangle, but I found these terms also applying to things unrelated to triangles 


#2
Mar1414, 04:33 PM

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Hello Newtons Apple!
When it is at angle θ, trig tells you that its height (above the centre) is h = rsinθ. If θ = ωt, with ω constant, then the height as a function of time is h = rsinωt … this is a sine wave! 


#3
Mar1414, 06:01 PM

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Click for animation  http://www.rkm.com.au/animations/ani...sinewave.html 


#4
Mar1414, 07:33 PM

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Sine Waves...Sine Angles
I concur with tinytim's and berkeman's explanations of "sine wave". I have never seen the phrase "sine angle". Do you mean "sine of an angle"?



#5
Mar1414, 09:31 PM

P: 43

That is...sort of mind blowing..I never really though of triangles as part of a circle...and a circle part of a wave..How is this possible?? But this is only valid for triangles with angles from 0 to 90 degree's right? Also when I see sin, or cos, or tan, in an equation, they themselves don't inherently have any value right? they just denote an operation to do on another number? I was always thinking that sin, cos,tang, etc.. actually have a value associated with them..like pi.



#6
Mar1414, 09:53 PM

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#7
Mar1414, 10:29 PM

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#8
Mar1514, 03:23 AM

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if θ is between 90° and 180°, that height is still positive, and shows that sin (180°  θ) = sinθ if θ is between 180° and 360°, that height is negative, and shows that sin (360°  θ) = sinθ 


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