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    Tanx=cosx

    -pi <x <pi
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    (Original post by ramshahk)
    Tanx=cosx

    -pi <x <pi
    Whats the identity for tanx?
    Should be able to form a quadratic from that.
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    (Original post by an_atheist)
    Whats the identity for tanx?
    Should be able to form a quadratic from that.
    -pi <x <pi
    How would you form a quadratic
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    (Original post by ramshahk)
    -pi <x <pi
    How would you form a quadratic
    tanx=sinx/cosx
    in the question tanx=cosx, so sinx/cosx=cosx. If we bring the cosx up, we get sinx=(cosx)^2. What other identity can you use?
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    (Original post by an_atheist)
    tanx=sinx/cosx
    in the question tanx=cosx, so sinx/cosx=cosx. If we bring the cosx up, we get sinx=(cosx)^2. What other identity can you use?
    The question says -pi <x<pi
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    (Original post by ramshahk)
    The question says -pi <x<pi
    That's a limit on the range of values x can take. In theory there are an infinite number of points where tanx=cosx.
    For the minute, ignore it.
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    (Original post by an_atheist)
    That's a limit on the range of values x can take. In theory there are an infinite number of points where tanx=cosx.
    For the minute, ignore it.
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    Tanx = Cosx

    Sinx / Cosx = Cosx

    Sinx = Cos^2x

    Sinx = 1 - Sin^2x

    Sin^2x + Sinx - 1 = 0

    Let y = sinx

    y^2 + y - 1 = 0

    i think this is how u do it but i probably made a mistake somewhere


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    (Original post by DamnDaniel2)
    Tanx = Cosx

    Sinx / Cosx = Cosx

    Sinx = Cos^2x

    Sinx = 1 - Sin^2x

    Sin^2x + Sinx - 1 = 0

    Let y = sinx

    y^2 + y - 1 = 0

    i think this is how u do it but i probably made a mistake somewhere


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    Looks good. Just trying to avoid giving this guy the answer on a plate, since it will help him more in the long run.
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    (Original post by an_atheist)
    Looks good. Just trying to avoid giving this guy the answer on a plate, since it will help him more in the long run.
    Yh I realised after! So sorry

    Should've given the first 2 steps or just the identity they should've used and then left it there


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