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Math Help - Sum and Difference Formulas

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    Sum and Difference Formulas

    There's a problem in my textbook- find the sine,cosine,tangeant, for 105=60+45 (all angles)

    I put in the sine of 105 in my calculator and got the same number when I entered the exact answer that I got: √6 +√2/4. The answer they want for the sine of 105 is √2/4(√3+1), and it's in the same format for 30 more questions and I can't figure out how to put it in a different(and more complicated) form. Can someone show me how to convert my answer into the book's answer?
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    Quote Originally Posted by clay10 View Post
    There's a problem in my textbook- find the sine,cosine,tangeant, for 105=60+45 (all angles)

    I put in the sine of 105 in my calculator and got the same number when I entered the exact answer that I got: √6 +√2/4. The answer they want for the sine of 105 is √2/4(√3+1), and it's in the same format for 30 more questions and I can't figure out how to put it in a different(and more complicated) form. Can someone show me how to convert my answer into the book's answer?
    factor out \sqrt{2} from the two terms in the numerator ...

    \frac{\sqrt{6} + \sqrt{2}}{4} = \frac{\sqrt{2}(\sqrt{3} + 1)}{4}

    in future, please use parentheses as grouping symbols or learn how to post in Latex.
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