Bike Forums > Foo > How do you figure sine, cosine, and tangent, with out a calculator?
 Register All Albums Elite Membership Forum Rules Calendar Search Today's Posts Mark Forums Read

 Foo Off-Topic chit chat with no general subject.

 12-08-04, 10:58 PM #1 ChAnMaN Specialized Member Thread Starter     Join Date: Nov 2003 Location: I live in a small town Bikes: 2004 Specialized Allez Posts: 973 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) How do you figure sine, cosine, and tangent, with out a calculator? ok so today in math we are working with sine, cosine, and tangent long story short i asked the teacher how to figure it out with out the use of a calculator and his response was the "you dont" in a way like he was telling me i wouldnt be able to understand. this made me really mad so i looked online but i couldnt find it on the internet either so i was hoping maybe some math wiz here would be able to tell me the answer. thanks ChAnMaN __________________ You can never be too Specialized Click here if any of the following apply to you: 1 You dont like Specialized, 2 You drive a SUV, 3 Your name is George Bush
 12-08-04, 11:01 PM #2 slvoid 2-Cyl, 1/2 HP @ 90 RPM     Join Date: Oct 2003 Location: NYC Bikes: 04' Specialized Hardrock Sport, 03' Giant OCR2 (SOLD!), 04' Litespeed Firenze, 04' Giant OCR Touring, 07' Specialized Langster Comp Posts: 15,762 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) Sohcahtoa. Sin=Opposite/Hypotenuse. Cos=Adjacent/Hypotenuse. Tan=Opposite/Adjacent.
 12-08-04, 11:05 PM #3 ChAnMaN Specialized Member Thread Starter     Join Date: Nov 2003 Location: I live in a small town Bikes: 2004 Specialized Allez Posts: 973 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) no not like that i understand soh cah toa i mean acutlay calculate it like cos34=? normaly on your calculator you push "cos" , push 34, hit enter and it spits out a number i want to know the equation that goes into that __________________ You can never be too Specialized Click here if any of the following apply to you: 1 You dont like Specialized, 2 You drive a SUV, 3 Your name is George Bush
 12-08-04, 11:09 PM #4 trekkie820 Senior Member   Join Date: Feb 2004 Location: Cleveland, OH Bikes: 2004 Trek 4600, 1980's Univega Supra Sport, 2006 Lemond Reno Posts: 2,287 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) Do you own a calculator that will do it? Yes=Don't worry about it. No=Don't worry about it. If you are in high school, a word of advice. After your college courses in these areas, trig is USELESS.
 12-08-04, 11:10 PM #5 CdCf Videre non videri   Join Date: Sep 2004 Location: Gothenburg, Sweden Bikes: 1 road bike (simple, light), 1 TT bike (could be more aero, could be lighter), 1 all-weather commuter and winter bike, 1 Monark 828E ergometer indoor bike Posts: 3,208 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s)
 12-08-04, 11:20 PM #6 JavaMan Senior Member     Join Date: Sep 2004 Location: Southern California Bikes: 2013 KHS Flite 747 Posts: 1,068 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) You can calculate it (not advised) or you can look it up in a table. Before calculators, we used trig tables. http://www.math2.org/math/trig/tables.htm It's very simple to use a table like this, but you have to interpolate if you want a value in between the table listings. Tom
12-08-04, 11:21 PM   #7
CRUM
Recovering Retro-grouch

Join Date: Dec 2003
Location: Some call it God's country. I call it Acton, Maine
Bikes: Too Many - 7 or 8
Posts: 5,008
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
 Originally Posted by CdCf http://www.homeschoolmath.net/other_...calculator.php
Cool Site. Thanks.
__________________
Keep it 'tween the ditches

My Blog - Lost in the Bo Zone

12-08-04, 11:23 PM   #8
bikeNaround
Junior Member

Join Date: Sep 2003
Bikes:
Posts: 10
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
 Originally Posted by trekkie820 If you are in high school, a word of advice. After your college courses in these areas, trig is USELESS.
Not true for many professions. Maybe useless to you but not to everyone.

 12-08-04, 11:26 PM #9 CdCf Videre non videri   Join Date: Sep 2004 Location: Gothenburg, Sweden Bikes: 1 road bike (simple, light), 1 TT bike (could be more aero, could be lighter), 1 all-weather commuter and winter bike, 1 Monark 828E ergometer indoor bike Posts: 3,208 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) Pretty easy to set up in Excel as well. It took me about a minute.
 12-08-04, 11:26 PM #10 CRUM Recovering Retro-grouch     Join Date: Dec 2003 Location: Some call it God's country. I call it Acton, Maine Bikes: Too Many - 7 or 8 Posts: 5,008 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) Just because we choose not to use knowledge, doesn't make it useless. I think it is great you are trying to know more than "punch this button and this will happen". Keep that curious nature. It will only help you down the road. __________________ Keep it 'tween the ditches My Blog - Lost in the Bo Zone
 12-08-04, 11:28 PM #11 Swiss Hoser Senior Member   Join Date: Mar 2004 Location: Schweiz Bikes: Pinarello Treviso, Rocky Mountain Oxygen Posts: 180 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) The link to "homeschoolmath" identifies it as a Taylor series. It's actually a special case of this called the Maclaurin series.
 12-08-04, 11:50 PM #12 ChAnMaN Specialized Member Thread Starter     Join Date: Nov 2003 Location: I live in a small town Bikes: 2004 Specialized Allez Posts: 973 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) hey thanks for the homeschoolmath link, im playing with it right now to see if i understand the equation completely __________________ You can never be too Specialized Click here if any of the following apply to you: 1 You dont like Specialized, 2 You drive a SUV, 3 Your name is George Bush
 12-09-04, 04:45 AM #13 blendingnoise Ubermensch     Join Date: Aug 2004 Location: philly Bikes: ye old centurion Posts: 258 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) If it is certian angles or combinations of known angles (45, 30) you can figure out a solution using a law whose name I forget. It goes something like sin(75) = sin45 + sin30 and then using the basic 45/45/90 and the 60/30/90 triangles you can get a solution. It has been a year since I did trig but I do remember that part. Back when I was in India we had to look up logs in these log table books which was not fun during exams and such. Good for basics and understanding but a calculator is much more helpful for calculations like those.
 12-09-04, 06:44 AM #14 Applehead57 slower than you     Join Date: Mar 2004 Location: dairy country NY Bikes: Gunnar Road Sport, peugeot UO-10 Posts: 652 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) I never understood that stuff. My math teachers never related it to real life, all I understood was that I was trying to find the length of line A-B. Why would anyone care? Now, I realize that I could have found the height of a tree or house. Well, ok, I wasn't too bright, no brilliant leaps of logic here.
 12-09-04, 07:05 AM #15 slvoid 2-Cyl, 1/2 HP @ 90 RPM     Join Date: Oct 2003 Location: NYC Bikes: 04' Specialized Hardrock Sport, 03' Giant OCR2 (SOLD!), 04' Litespeed Firenze, 04' Giant OCR Touring, 07' Specialized Langster Comp Posts: 15,762 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) You can probably do this with algebra. It's all just a ratio, so knowing that a given angle in a right-triangle can go from just above 0 to just below 90 degrees, you can setup a ratio of the sides then subdivide that through the 0-90 degrees, the smaller your subdivision, the more precise your answer.
 12-09-04, 10:08 AM #16 H23 Senior Member     Join Date: Sep 2004 Location: Baltimore Bikes: bianchi Posts: 1,101 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) Here is a nice list of expansions for common trig functions.... http://mathworld.wolfram.com/MaclaurinSeries.html A nice thing about expansions is that you can often approximate a numerical computation by expanding the special functions (trig functions) and using only the first couple of terms (if you know subsequent terms are vanishingly small). In the before time, that's what people did to make some calculations tractable.
 12-10-04, 01:48 AM #17 iamlucky13 Footballus vita est     Join Date: Jun 2002 Location: Portland, OR Bikes: Trek 4500, Kona Dawg Posts: 2,118 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) "Trig is USELESS" Hehe...not quite. Some of the stuff you use it for are a little mundane, like designing the chair you are sitting on, but some are kind of cool, like solving differential equations that describe the wave motion of light, an understanding that led to the invention of lasers and CD players. __________________ "The internet is a place where absolutely nothing happens. You need to take advantage of that." ~ Strong Bad
 12-10-04, 10:35 AM #18 PanPanX Ride On!!     Join Date: Oct 2004 Location: Temple City, CA Bikes: 2004 OCR3, 1989 Nishiki Sport, 2003 Kona Blast, 2007 Fuji Track Posts: 467 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) you learn something called the unit circle. 99.9% of the time when you do trig problems, and you're not allowed to use a calculator, they're 'special' ones that have values like pi/4, pi/3, pi/6, pi/2, 1, 0, 3pi/2, etc etc etc. just learn the unit circle, and know a tiny bit of algebra and you can solve all the 'special ones'. and what i mean by that, is you can solve for the sin, cos, tan, csc, sec, cot, arcsin, arccos, arctan, arccsc, arcsec, arccot of 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 45, 135 degrees and for everything else, you have to use some equations and whatnot. some trig identies, and properties, and you'll be set. a common trig idenity is (sinX)^2 + (cosX)^2 = 1 you'll be learning a lot of this when you take PreCalc and Calc. and whoever said Trig is useless after college corses and stuff is completely wrong. electrians use the cos curve everyday to calculate the power and watts and such that you need. circuts, your house, everything, is all calculated by either using sin or cos curves. of course if you're flipping burgers, its completely useless.. unless you're really sick and demented and lke to flip your burgers at a certain trig curve or like to compare the steam different trig curves.. hehe also, you know the button on your calculator that changes it from DEG, RAD and (something else i cant think of off the top of my head). the Degree stands for Degrees and Rad stands for Radians, and the other thing is used for Mech Engineers to calculate certain things.. but later on you'll learn to solve trig stuff in degrees and in radians mode. right now you're probably just using degrees Last edited by PanPanX; 12-10-04 at 10:49 AM.
 12-10-04, 11:28 AM #19 H23 Senior Member     Join Date: Sep 2004 Location: Baltimore Bikes: bianchi Posts: 1,101 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) I think the guy that was saying trig was useless after college courses, was trying to say that there is so much more to math that at some point all the things you learned in high school math are nothing more than tiny fragments of the big picture in math. To the kiddies out there... stick with it if you have an inclination for math, there is a lot more to it, and it does get vastly more interesting.
12-10-04, 04:06 PM   #20
iamlucky13
Footballus vita est

Join Date: Jun 2002
Location: Portland, OR
Bikes: Trek 4500, Kona Dawg
Posts: 2,118
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
 Originally Posted by H23 ...and it does get vastly more interesting.
Right up until you get to partial differential equations and get stuck with a teacher who doesn't seem to realize his method is less like teaching you how to solve PDE's than it is discussing different methods with you as though you were his acedemic peer. I just need to repeat to myself "I will pass the final, I will pass the final..." and spend all of the next 5 days studying. It's a pity because I was really excited about taking this class at the beginning of the semester.
__________________
"The internet is a place where absolutely nothing happens. You need to take advantage of that." ~ Strong Bad

12-10-04, 04:33 PM   #21
PanPanX
Ride On!!

Join Date: Oct 2004
Location: Temple City, CA
Bikes: 2004 OCR3, 1989 Nishiki Sport, 2003 Kona Blast, 2007 Fuji Track
Posts: 467
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
 Originally Posted by iamlucky13 Right up until you get to partial differential equations and get stuck with a teacher who doesn't seem to realize his method is less like teaching you how to solve PDE's than it is discussing different methods with you as though you were his acedemic peer. I just need to repeat to myself "I will pass the final, I will pass the final..." and spend all of the next 5 days studying. It's a pity because I was really excited about taking this class at the beginning of the semester.
yea.. i was like that.. i used to think math was cool and fun and interseting.. but then i had a crappy teacher and now i dont even know if im going to pass..

12-10-04, 07:11 PM   #22
LordOpie
Senior Member

Join Date: Jun 2004
Location: Denver
Bikes: 2006 custom Walt Works roadie, 2003 Fuji Finest (road), 2002 Giant Iguana (mtb), 1986 BMW K75 (motor)
Posts: 3,698
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
Quote:
 Originally Posted by trekkie820 Do you own a calculator that will do it? Yes=Don't worry about it. No=Don't worry about it. If you are in high school, a word of advice. After your college courses in these areas, trig is USELESS.

 12-10-04, 09:50 PM #23 GeezerGeek Senior Member     Join Date: Sep 2004 Location: Minnesota Bikes: 1993 Infinity LWB, Bacchetta Posts: 224 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) I used a slide rule to find trig functions when I was in school.
12-14-04, 01:42 PM   #24
Swiss Hoser
Senior Member

Join Date: Mar 2004
Location: Schweiz
Bikes: Pinarello Treviso, Rocky Mountain Oxygen
Posts: 180
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
 Originally Posted by GeezerGeek I used a slide rule to find trig functions when I was in school.
So did I.
Man, am I glad those days are gone!

 12-23-04, 11:21 AM #25 parrothead Newbie     Join Date: Mar 2003 Location: Bowmanville Ontario Bikes: Schwinn Mesa GSX Posts: 3 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) Unless you become a surveyor, or engineer.