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jamonathin

Wed May 25, 2005 5:52 pm


[Help] Exact Value - Trig Question

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Hey guys, whats goin on.  I have a big ass calc. test tomorrow and I have no idea how to figure out exact values.  And yesh I know I prolyl have a lot of other things I need to work on, but i'm incredibly retarded.

Here's a chart I found on the [url=http://www-pub.naz.edu:9000/~ebremer2/lesson%20number%20four%20warm%20up.pdf]internet.  If anyone can fill that badboy in or at least tell me how to find exact values of cosine, sine and tangent, that'd be great.

Thanks for your help :)


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wtd

Wed May 25, 2005 6:16 pm



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How do you find exact values?  Keep things in terms of fractions.  Fractions are exact.


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jamonathin

Wed May 25, 2005 6:22 pm



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that's what I dont know, you're supposed to "remember them".

All i know is that sin(pi)/6 = 1/2  :?


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wtd

Wed May 25, 2005 6:29 pm



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Ah.  Well, remember cosine and sine and you have tangent.

For cosine and sine, visualize the waves.  That won't give you the exact value, but it'll let you see the basic pattern, which will make it easier to retain the specifics in your mind.  :)


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jamonathin

Wed May 25, 2005 6:34 pm



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Ok, so basically the waves will tell me the size of the fraction, like if it should be big or not.


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brenn

Wed May 25, 2005 6:38 pm



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Eh.. I'm probably not the best person to be teaching you math.  But here goes.

Have you ever learnt about the "special triangles" that can help you "calculate" the cosines, sines, and tangents of select angles?

Since you're learning trigonometry, I'll assume you know what a right angle triangle is.

First:  Draw an isoceles right angle triangle and label the angle as such:   90, 45 and 45 (in degrees).   Now you label the sides:  

1)  Two of the side lengths are equal.   Label these as "1".
2)  Using Pythagorean Theorem, you  know that the third side is root(2).

Since 

Sine = Opposite / Hypoteneuse

sin45 = 1/root(2)          