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

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.
texastoast101
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If sin(x)=root2/root3 and cos(x)>0, find sin (2x)

Postby texastoast101 » 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.

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stapel_eliz
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Postby stapel_eliz » Wed May 18, 2011 3:01 pm

texastoast101 wrote: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)?

texastoast101 wrote: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?

texastoast101
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Re: If sin(x)=root2/root3 and cos(x)>0, find sin (2x)

Postby texastoast101 » Wed May 18, 2011 4:11 pm

this is all i was given i have no idea

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stapel_eliz
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Postby stapel_eliz » Thu May 19, 2011 1:55 am

texastoast101 wrote: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. :wink:


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