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    For c I've shown that arg(w+1+2i)=pi/4 however the answer says it's 3pi/4

    For d I've shown that z+2=1/w by rearranging to find z and adding on +2 however i can't seem to get arg(w)=-PI/4


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    Sorted part c.
    For d i get arg(1)-arg(w)=pi/4



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    (Original post by Mutleybm1996)
    Sorted part c.
    For d i get arg(1)-arg(w)=pi/4



    Posted from TSR Mobile
    for c factorize the -i out

    split the arg

    arg(-i) = -pi/2

    -pi/2 + arg(w+1+2i) = pi/4


    edit too late
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    (Original post by TeeEm)
    for c factorize the -i out

    split the arg

    arg(-i) = -pi/2

    -pi/2 + arg(w+1+2i) = pi/4


    edit too late
    Argh, being so stupid! I've just realised how to do d too thanks though


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    (Original post by Mutleybm1996)
    Sorted part c.
    For d i get arg(1)-arg(w)=pi/4



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    for d

    z+2 = 1/w
    arg(z+2) = arg(1/w)
    pi/4 = arg(1/w)
    pi/4 = -arg(w)
    argw = -pi/4
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    (Original post by TeeEm)
    for d

    z+2 = 1/w
    arg(z+2) = arg(1/w)
    pi/4 = arg(1/w)
    pi/4 = -arg(w)
    argw = -pi/4
    Could you possibly have a look at 4c/d? My working is attached
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    (Original post by Mutleybm1996)
    Could you possibly have a look at 4c/d? My working is attached
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    I can only see (c) and I disagree (I think)
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    (Original post by TeeEm)
    I can only see (c) and I disagree (I think)
    Could you possibly provide a hint?


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    (Original post by Mutleybm1996)
    Could you possibly provide a hint?


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    second line from the bottom

    in the LHS i think you lost the denominator
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    (Original post by TeeEm)
    second line from the bottom

    in the LHS i think you lost the denominator
    So i now have 1=mod(iw-2w+2i)
    Any advice on where to go from here?
    Would i say 1=mod(i(w+2)-2w)?

    Weird, the Book says the answer is mod(w-1/5 (-2+4i))=1/sqrt5

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    (Original post by Mutleybm1996)
    So i now have 1=mod(iw-2w+2i)
    Any advice on where to go from here?
    Would i say 1=mod(i(w+2)-2w)?


    Posted from TSR Mobile
    it is a nasty circle

    either put w=u+iv and simplify

    or


    factorize the coefficient of w
    then pull it out of the mod

    etc

    harder
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    (Original post by TeeEm)
    it is a nasty circle

    either put w=u+iv and simplify

    or


    factorize the coefficient of w
    then pull it out of the mod

    etc

    harder
    Well now I have absolutely no idea!
    Sorry...I'm probably just being useless
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    (Original post by Mutleybm1996)
    Well now I have absolutely no idea!
    Sorry...
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    Posted from TSR Mobile
    it is correct so far

    |A(u,v) + iB(u,v)| = 1

    SRoot(A2+B2) = 1

    square both sides etc
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    (Original post by TeeEm)
    it is correct so far

    |A(u,v) + iB(u,v)| = 1

    SRoot(A2+B2) = 1

    square both sides etc
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    Is this any closer?


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    (Original post by Mutleybm1996)
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    Is this any closer?


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    your method is correct but you have made silly computational errors.

    If you supply an email address and I will post the solution (2 methods)
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    (Original post by Mutleybm1996)
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    Is this any closer?


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    look at the alternative method in purple
    (this approach is a bit hard for students generally)
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    (Original post by TeeEm)
    look at the alternative method in purple
    (this approach is a bit hard for students generally)
    I understand the principle, whether I'd be able to reproduce it is another matter!
    Thanks, I may post again if I get stuck on 4d


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    (Original post by Mutleybm1996)
    I understand the principle, whether I'd be able to reproduce it is another matter!
    Thanks, I may post again if I get stuck on 4d


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    my pleasure
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    (Original post by TeeEm)
    my pleasure
    Hi, for d I managed to find and plot the two points easily enough, however don't quite understand what the 3pi/4 has to do with the problem?


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    (Original post by Mutleybm1996)
    Hi, for d I managed to find and plot the two points easily enough, however don't quite understand what the 3pi/4 has to do with the problem?


    Posted from TSR Mobile
    I have not got a clue which question you are referring to ...

    post the workings for this question
 
 
 
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