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C2 Maths help with trigonometric functions Watch

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    Stuck on this question For 0<theta<2pie Solve 3cos^2 theta - 13cos theta = 3sin^2 theta - 9

    I was wondering if you have to use the tan identity or just the normal one and how would you use it for this question
    Many thanks
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    (Original post by washdog)
    Stuck on this question For 0<theta<2pie Solve 3cos^2 theta - 13cos theta = 3sin^2 theta - 9

    I was wondering if you have to use the tan identity or just the normal one and how would you use it for this question
    Many thanks
    Express sin^2(theta) in the form 1-cos^2(theta)

    Btw its pi not pie
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    (Original post by joostan)
    Express sin^2(theta) in the form 1-cos^2(theta)

    Btw its pi not pie


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    (Original post by washdog)
    Stuck on this question For 0<theta<2pie Solve 3cos^2 theta - 13cos theta = 3sin^2 theta - 9

    I was wondering if you have to use the tan identity or just the normal one and how would you use it for this question
    Many thanks
    3cos^2P -13cosP=3(1-Cos^2(P))-9

    6Cos^2P-13CosP+6=0

    CosP=13+-5/12

    CosP=8/12 OR 18/12

    P=0.841068671
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    Lol thanks guys i just did this on myself after joostans help well proud ;D especially after teacher did "trigonometric functions" in 2 lessons oh well many thanks
 
 
 
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