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June 28th, 2014, 10:23 AM   #1
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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!
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June 28th, 2014, 11:17 AM   #2
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Quote:
Originally Posted by teetar View Post
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.
It can't be done. I'd use a calculator.
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June 28th, 2014, 07:02 PM   #3
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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.
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June 28th, 2014, 08:12 PM   #4
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Old Skool

You can use an old skool analog calculator.



Sine 80° ≈ 0.985

Notice:
Sine 30° = 0.5

Virtual Pickett N909-ES SIMPLEX TRIG RULE with METRIC CONVERSION Slide Rule
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