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Math Help - I need help with trig

  1. #1
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    I need help with trig

    IV BEEN WORKING ON THESE QUESTIONS FOR A VERY LONG TIME AND I CANT GET THE ANSWERS.

    A) CALCULATE SIN225+COS120-TAN(-330)

    B) (COS30)(COS30)=(SIN30)(SIN30)

    I DONT KNOW HOW BUT LEFT HAS TO BE EQUAL TO RIGHT FOR PART B
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  2. #2
    Super Member

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    Lexington, MA (USA)
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    Hello, Viviana!

    A) Calculate: . \sin225^o+\cos120^o-\tan(\text{-}330^o)
    You're expected to know the trig values of "standard angles."

    . . \begin{array}{ccccc}\sin225^o &=&\text{-}\sin45^o &=& \text{-}\frac{\sqrt{2}}{2}\\ \\[-4mm]<br /> <br />
\cos 120^o &=&\text{-}\cos60^o &=&\text{-}\frac{1}{2} \\ \\[-4mm]<br /> <br />
\tan (\text{-}330^o) &=&\tan30^o &=&\frac{\sqrt{3}}{3} \end{array} \quad\hdots\;\text{ etc.}





    B)\;\;(\cos30^o)(\cos30^o) \:=\:(\sin30^o)(\sin30^o) . ??

    I DONT KNOW HOW BUT LEFT HAS TO BE EQUAL TO RIGHT FOR PART B
    That is quite impossible . . . equivalent to: 3 = 1



    AND TAKE OFF YOUR CAPS-LOCK.

    . . IT'S IMPOLITE TO SHOUT.

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