Subject:
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Re: Off on a tangent (or a sine, anyway)
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Tue, 16 Jan 2001 19:46:34 GMT
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Viewed:
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85 times
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In lugnet.off-topic.geek, Dave Schuler writes:
> I'm working on something that's taxing my limited knowledge of trig
> functions, so forgive me if my terminology is a little messed up:
> I need to graph a sine function with a wavelength of 324 and an amplitude
> of 120 passing through point (0,180) at a maximum and (162,0) at a minimum.
> I've been messing around with some graphing software, but I can't get it
> quite right. Can anyone help one of the math-illiterate?
> Thanks a whole bunch!
>
> Dave!
I'm a little rusty myself, but there are bits and pieces here that don't
quite add up, I think.
Having a wavelength of 324 (I'm assuming you mean degrees, although you
without stating degrees normally means radians) in which case your sin
(well, more likely cos function since the max occurs at x = 0) starts off
with something like
y = cos(10/9 x) (approx cos (1.11 x))
an amplitude of 120 means it's now
y = 120 cos (1.11 x)
this is where it starts to get weird.
You say max is at (0,180) and min is (162,0)... that gives an amplitude of
90 if max y is 180 and min y is 0, which contradicts your previous
requirement for amplitude of 120?? If you want the max to occur at 180,
y = 120 cos (1.11 x) + 60 will give you that starting point, and will give
you a minimum at x = 162, but it will be (162, -60), not (162, 0).
If you want a wavelength of 324 and it passes through both points,
y = 90 cos (1.11 x) + 90 will give you the right equation. (But amplitude is
now 90, not 120)
But either 1 of the conditions you set is mutually exclusive from the
others, or I'm simply misunderstanding (I am a little rusty) but perhaps you
could further elaborate from here what your specific needs are?
Mark W.
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Message has 1 Reply:
 | | Re: Off on a tangent (or a sine, anyway)
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| (...) Doh! I was trying to be so careful! I thought amplitude was the "height" from high to low--is it actually half that? At any rate, I meant to write the min occurs at y=60, so that the high points occur along the line y=180 and the low points (...) (24 years ago, 16-Jan-01, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Off on a tangent (or a sine, anyway)
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| I'm working on something that's taxing my limited knowledge of trig functions, so forgive me if my terminology is a little messed up: I need to graph a sine function with a wavelength of 324 and an amplitude of 120 passing through point (0,180) at a (...) (24 years ago, 16-Jan-01, to lugnet.off-topic.geek)
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