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### If sin(x)=root2/root3 and cos(x)>0, find sin (2x)

Posted: Wed May 18, 2011 1:11 pm
If sin(x)=root2/root3 and cos(x)>0, find sin (2x)

If csc x=-(4/3), and x terminates in quadrant IV, find tan(x)

Can somone help me with these problems i do not have a clue how to do them and my teacher is no help.

Posted: Wed May 18, 2011 3:01 pm
If sin(x)=root2/root3 and cos(x)>0, find sin (2x)
What identity do you have for sin(2x) in terms of sine and cosine? If sin(x) = sqrt[2]/sqrt[3], then what is the length of the third side of the reference triangle? Then what is the value of the cosine for that triangle? What then is the value of sin(2x)?
If csc x=-(4/3), and x terminates in quadrant IV, find tan(x)
What is the length of the third side of the triangle? Given that x is in the fourth quadrant, what are the signs on the legs of the triangle? What then is the value of the tangent?

### Re: If sin(x)=root2/root3 and cos(x)>0, find sin (2x)

Posted: Wed May 18, 2011 4:11 pm
this is all i was given i have no idea

Posted: Thu May 19, 2011 1:55 am
this is all i was given i have no idea
My questions were hints, referring to topics covered in your trigonometry class. By answering those questions, you should be able to answer the exercises.