Posted by **Lucy** on Saturday, April 19, 2008 at 4:17pm.

1) Find the exact value of cos 105 degrees by using a half-angle formula.

2)Find the solution of sin 2theta = cos theta if 0 degrees</= theta < 180 degrees.

I have read the book and looked at the examples, but cannot figure out how to work these. Any help would be great!!

Thanks

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