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Math Help - sin and cos 45 degress

  1. #1
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    sin and cos 45 degress

    ok the book quotes sin and cos of 45 degress as 1/sqrt 2, but my calculator give the answer of 2/sqrt 2
    I`m convinced the book is wrong , or am I nuts?
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  2. #2
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    Re: sin and cos 45 degress

    Quote Originally Posted by davellew69 View Post
    ok the book quotes sin and cos of 45 degress as 1/sqrt 2, but my calculator give the answer of 2/sqrt 2
    I`m convinced the book is wrong , or am I nuts?
    Both answers are correct as the two expressions are equivalent.

    \displaystyle \begin{align*} \frac{1}{\sqrt{2}} = \frac{1 \cdot \sqrt{2}}{\sqrt{2}\cdot\sqrt{2}} = \frac{\sqrt{2}}{2} \end{align*}
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  3. #3
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    Re: sin and cos 45 degress

    thanks, I thought I was going nuts
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  4. #4
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    Re: sin and cos 45 degress

    Did it ever occur to you to evaluate both 1/sqrt(2) and sqrt(2)/2 on your calculator?
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