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June 28th, 2014, 11:23 AM  #1 
Newbie Joined: Jun 2014 From: earth Posts: 11 Thanks: 0  How Do You Find Sine of Angle in Unit Circle w/o Calculator
I understand that unit circles shouldn't be too hard, however, I'm having quite a bit of trouble with the subject. I am doing some practice problems and I am completely confused. They're asking me to use a unit circle to find the sine and cosine of various angles, however, I don't know if it's meant to be done with a calculator or without one. So I'm wondering if anyone could give me an example of how to find the cosine of 170 degrees for example, using a unit circle, without a calculator. Also, it's asking for answers simplified to 2 decimal places which is why I'm wondering if/how it could be done without a calculator. Any help will be greatly appreciated, so thanks!

June 28th, 2014, 12:17 PM  #2 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,885 Thanks: 1088 Math Focus: Elementary mathematics and beyond  
June 28th, 2014, 08:02 PM  #3 
Banned Camp Joined: Feb 2013 Posts: 224 Thanks: 6 
Off the top of my head, one way to do it is analog. The other way is to convert polar coordinates into Cartesian. But I forgot how that was done. 
June 28th, 2014, 09:12 PM  #4 
Banned Camp Joined: Feb 2013 Posts: 224 Thanks: 6  Old Skool
You can use an old skool analog calculator. Sine 80Â° â‰ˆ 0.985 Notice: Sine 30Â° = 0.5 Virtual Pickett N909ES SIMPLEX TRIG RULE with METRIC CONVERSION Slide Rule 

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