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Math Help - double-angle formula

  1. #1
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    double-angle formula

    just wondering how this equals 4.

    \frac{2sin2xcos2x}{(cos2x)\frac{1}{2}sin2x} = 4

    once again abit confused why that equals 4. thank u.
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  2. #2
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    Hello, jvignacio!


    You need to brush up on basic fractions . . .


    . . \frac{2(\sin2x)(\cos2x)}{(\cos2x)(\frac{1}{2})(\si  n2x)} \;=\;\frac{2({\color{blue}\rlap{/////}}\sin2x)({\color{red}\rlap{/////}}\cos2x)}{({\color{red}\rlap{/////}}\cos2x)(\frac{1}{2})({\color{blue}\rlap{/////}}\sin2x)} . =\;\frac{2}{\frac{1}{2}} \;=\;4

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  3. #3
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    Quote Originally Posted by Soroban View Post
    Hello, jvignacio!


    You need to brush up on basic fractions . . .


    . . \frac{2(\sin2x)(\cos2x)}{(\cos2x)(\frac{1}{2})(\si  n2x)} \;=\;\frac{2({\color{blue}\rlap{/////}}\sin2x)({\color{red}\rlap{/////}}\cos2x)}{({\color{red}\rlap{/////}}\cos2x)(\frac{1}{2})({\color{blue}\rlap{/////}}\sin2x)} . =\;\frac{2}{\frac{1}{2}} \;=\;4
    ahh crap i forgot to cancel out . thanks man
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