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    Hello could I have some help on trying to find the second possible solution for this question part c.




    This is what I have done:




    I thought of using cast but wasn't sure how to go about it.
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    (Original post by SirRaza97)
    I thought of using cast but wasn't sure how to go about it.
    If tan a = tan b, then a = b +n pi, where n is any integer.


    Use that and rearrrange to get theta = ..., then see what values you can get.
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    (Original post by ghostwalker)
    If tan a = tan b, then a = b +n pi, where n is any integer.


    Use that and rearrrange to get theta = ..., then see what values you can get.
    Woah where did this spooky rule come from?
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    (Original post by SirRaza97)
    Woah where did this spooky rule come from?
    Er, you should have a section in your book that deals with the general solutions of things like sin A = sin B, cos A = cos B and tan A = tan B

    Alternatively, you should be able to recognize the periodicity of tan x from its graph.
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    (Original post by SirRaza97)
    ...
    You seem to be under the impression that if you have tan a = tan b, then it must be only the case that a = b.

    Whilst it is true that a = b does make the equation true, you should realise that tangent is a pi-periodic function, so if I wanted to, I could say that tan a = tan (b + pi). Since tan(b+pi) = tan(b).

    Otherwise, I would say that tan 1 = tan (1 + pi) and you'd sit there and tell me: "Hey! That means 1 = 1 + pi, i.e: 0 = pi. (illimunati)". You can clearly see that that is nonsense.

    So, if you have tan a = tan b, then you could have a = b, you could have a = b + pi, you could have a = b - pi, you could have a = b + pi + pi, you could have a = b - pi - pi, etc... onto infinite amounts of adding or subtracting pi's.
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    (Original post by Zacken)
    ....
    oh right so for sin and cos it would be 2pi and -2pi etc?
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    (Original post by SirRaza97)
    oh right so for sin and cos it would be 2pi and -2pi etc?
    Bang on.
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    (Original post by Zacken)
    Bang on.
    :eek3:


    Edit:
    E.g.

    sin(pi/3) = sin(2pi/3) so, pi/3 = 2pi/3 + 2npi
 
 
 
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