trigonometry

That is a kind of vague question. What kind of value are you looking for what? Do you have an equation? Or, do you want to input sin(2/3)?

It terms of the unit circle/radians, the sine value for the parent functions pi/3 is 60 degrees, pi/6 is 30 degrees, pi/4 is 45 degrees, 0 or 2pi is either 0 or 360 degrees, and pi/2 is 90 degrees.

I hope this helps. If you have a more definitive question, I could probably give you a clearer answer. Feel free to ask another question though.

If I understand the question, you have the value of the sine for some angle, but you don't know the angle. Just use the sine inverse button on your calculator ( You should be able to hit "2nd" and the "sin" button to find this. It's usually labeled as "asin" or ", "sin−1." Check your calculator manual, maybe??)

Be careful, though. The sine inverse has a range from -90 to 90 (in degrees) or from -pi/2 to pi/2 (in radians). Therefore, you need to be aware of which quadrant your angle lies. For instance, if the sine inverse gives you an angle of 30 degrees but your angle lies in the second quadrant, then you must SUBTRACT the 30 from 180 to get the correct angle, i.e., 150 degrees. The same applies to that angle in the 3rd quadrant....you must ADD the angle to 180 to get the correct angle, i.e., 210 degrees.

I hope this helps.

I meant to type....... if the sine inverse gives -30 degrees and your angle lies in the second quadrant, you must subtract 30 from 180!! I inadvertently left out the "minus" sign!! And if the sine inverse gives you 30 degrees and your angle lies in the 3rd quadrant, then you must add 30 to 180 to get the correct answer of 210.

Sorry for the confusion!!