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    Solve the equation tan θ = 2 sin θ for 0◦ ≤ θ ≤ 360◦

    I got up to: Sinx/Cosx=2Sinx


    the Mark scheme is attached and as always completely useless:
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    (Original post by TheAlphaParticle)
    Solve the equation tan θ = 2 sin θ for 0◦ ≤ θ ≤ 360◦

    I got up to: Sinx/Cosx=2Sinx


    the Mark scheme is attached and as always completely useless:
    Multiply both sides by cos(x), move everything to the same side then take out a factor of sin(x).
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    (Original post by notnek)
    Multiply both sides by cos(x), move everything to the same side then take out a factor of sin(x).
    What do you mean by that?
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    ^^^^ but then do not cancel out the sinx :naughty:
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    (Original post by TheAlphaParticle)
    What do you mean by that?
    Multiply everything by cos(x) gives:
    sin(x) = 2sin(x) cos(x)

    Take over to one side:
    0 = 2sin(x) cos(x) - sin(x)

    Take sin(x) outside of the bracket
    0 = sin(x)[2cos(x) -1]

    Now you have equate each part to 0 and solve:
    Let 0 = sin(x)
    Let 0 = 2cos(x) -1
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    (Original post by TheAlphaParticle)
    What do you mean by that?
    Um, you should really know what 'taking out a factor' is by now...
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    Out of interest, why are you currently revising C2? Which exam board are you doing?

    Or are you just doing this for fun?
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    (Original post by BasicMistake)
    Out of interest, why are you currently revising C2? Which exam board are you doing?

    Or are you just doing this for fun?
    I do OCR MEI and my C2 is next week. They just reversed the date of S1 and C2
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    (Original post by IrrationalRoot)
    Um, you should really know what 'taking out a factor' is by now...
    Not everyone learns it the same way, too my knowledge none of my teachers ever used that phrase nor have I ever needed to use it!
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    (Original post by BasicMistake)
    Multiply everything by cos(x) gives:
    sin(x) = 2sin(x) cos(x)

    Take over to one side:
    0 = 2sin(x) cos(x) - sin(x)

    Take sin(x) outside of the bracket
    0 = sin(x)[2cos(x) -1]

    Now you have equate each part to 0 and solve:
    Let 0 = sin(x)
    Let 0 = 2cos(x) -1
    Thanks for the detailed explanation!
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    (Original post by TheAlphaParticle)
    Not everyone learns it the same way, too my knowledge none of my teachers ever used that phrase nor have I ever needed to use it!
    How do you refer to taking out a factor from an expression then?
 
 
 
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