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secant and tangent line


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#1 HamsterPower

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Posted 8 February 2011 - 03:18 AM

In math and physics class i learned about secant and tangent lines(?)
i was wondering if this had anything to do with trigonometry

honestly, i don't really know what they are so confusing
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#2 steevey

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Posted 8 February 2011 - 03:23 AM

In math and physics class i learned about secant and tangent lines(?)
i was wondering if this had anything to do with trigonometry

honestly, i don't really know what they are so confusing


In trig, tangent is the opposite divided by the hypotenuse in a right triangle. In other words, its a relationship between the sides. Tangent is also a place that touches a circle or curve at only one point. In terms of a unit circle, its sin(x)/cos(x).

And a secant line is just a line that intersects a curve or circle at just two points.
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#3 alpha2cen

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Posted 8 February 2011 - 03:49 AM

In L(t) graph tangent line is a velocity v(t).
v(ti)=dL/dt|t=ti
And In v(t) graph tangent line is an acceleration a(t).
a(ti)=dv/dt|t=ti
Where
a; acceleration
L; length
v; velocity
t; time
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#4 imatfaal

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Posted 8 February 2011 - 06:39 PM

In trig, tangent is the opposite divided by the hypotenuse in a right triangle. In other words, its a relationship between the sides. Tangent is also a place that touches a circle or curve at only one point. In terms of a unit circle, its sin(x)/cos(x).

And a secant line is just a line that intersects a curve or circle at just two points.



NO!

Jeez! Tangent = Opposite over Adjacent.


For heaven's sake - Silly Old Harry, Caught A Herring, Trawling Off Afghanistan
SOH CAH TOA

Sin = Opposite over Hypotenuse Cos=Adjacent over Hypotenuse Tan = Opposite over Adjacent

take a right-angled triangle - the side that does not touch your angle is the opposite, the long side is the hypotenuse and the short side that touches your angle is the adjacent.

The secant is the reciprocal of the cosine function ie 1/cos - ie hypotenuse over adjacent.

This is basic trig HamsterPower

the tangent and secant have other definitions as well . The Tangent is a line that "just touches" a curve - this is the same as saying it is perpendicular to the curve at that single point. the secant is a line that cuts a curve twice. But I would think that your teacher was talking about basic trigonometry. It's worth learning - it seems abstract at first, but it is incredibly useful. If you are having trouble make a post in the homework forum and I am sure people will talk you through it

And Steevey - if you don't know don't answer

Edited by imatfaal, 8 February 2011 - 10:58 PM.

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#5 steevey

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Posted 9 February 2011 - 01:03 AM

NO!

Jeez! Tangent = Opposite over Adjacent.


For heaven's sake - Silly Old Harry, Caught A Herring, Trawling Off Afghanistan
SOH CAH TOA

Sin = Opposite over Hypotenuse Cos=Adjacent over Hypotenuse Tan = Opposite over Adjacent

take a right-angled triangle - the side that does not touch your angle is the opposite, the long side is the hypotenuse and the short side that touches your angle is the adjacent.

The secant is the reciprocal of the cosine function ie 1/cos - ie hypotenuse over adjacent.

This is basic trig HamsterPower

the tangent and secant have other definitions as well . The Tangent is a line that "just touches" a curve - this is the same as saying it is perpendicular to the curve at that single point. the secant is a line that cuts a curve twice. But I would think that your teacher was talking about basic trigonometry. It's worth learning - it seems abstract at first, but it is incredibly useful. If you are having trouble make a post in the homework forum and I am sure people will talk you through it

And Steevey - if you don't know don't answer


Dude, chill out, I accidentally messed up. Should I go exploding on you because you said a tangent is when it "just touches"? It's like saying to a math teacher there's "space" inside a 2D shape, rather than its just an enclosed region. I also mentioned a unit circle too, which I could only know that the reason tangent doesn't work at 90 degrees is because your doing 1/0, which means I know how to use it anyway.

But what was it about tangent in radians? Cause I know you can use tangent with them, but I don't remember what it does.

Edited by steevey, 9 February 2011 - 01:39 AM.

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#6 imatfaal

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Posted 9 February 2011 - 12:08 PM

Steevey

read the first paragraph http://en.wikipedia.org/wiki/Tangent - or read the 7-8th line http://mathworld.wol...om/Tangent.html The reason you shouldn't explode is that just touches or touches is a fairly recognized phrasing for describing a tangent line.
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A little learning is a dangerous thing; drink deep, or taste not the Pierian spring:
there shallow draughts intoxicate the brain, and drinking largely sobers us again.

- Alexander Pope

 

feel free to click the green arrow  ---->

 


#7 steevey

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Posted 9 February 2011 - 01:29 PM

Steevey

read the first paragraph http://en.wikipedia.org/wiki/Tangent - or read the 7-8th line http://mathworld.wol...om/Tangent.html The reason you shouldn't explode is that just touches or touches is a fairly recognized phrasing for describing a tangent line.


According to wikipedia. Why why do you care so much as to completely change the topic?
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