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    I dont suppose anybody on here has any good resources for representing modulus and argument on argand diagrams? I feel this is the main topic holding me back in fp1

    I cant seem to get my head around my textbook (OCR)

    I cant even represent |z|=|z-8| on an argand diagram, if anyone has a worked solution to that id really appreciate it :')))
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    (Original post by emilyp2206)
    I dont suppose anybody on here has any good resources for representing modulus and argument on argand diagrams? I feel this is the main topic holding me back in fp1

    I cant seem to get my head around my textbook (OCR)

    I cant even represent |z|=|z-8| on an argand diagram, if anyone has a worked solution to that id really appreciate it :'))
    http://www.examsolutions.net/maths-r...FP1/module.php you have maybe seen this site before, but i recommend watching the videos and pausing them to do all the questions, then you effectively have past paper questions with worked solutions

    as for |z|=|z-8|, have you been taught to solve this by squaring both sides, or to consider what happens when z<8 and when z>8 separately
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    (Original post by DylanJ42)
    http://www.examsolutions.net/maths-r...FP1/module.php you have maybe seen this site before, but i recommend watching the videos and pausing them to do all the questions, then you effectively have past paper questions with worked solutions

    as for |z|=|z-8|, have you been taught to solve this by squaring both sides, or to consider what happens when z<8 and when z>8 separately
    not that i remember, the first time ive met squaring both sides was just now when looking in the textbook:/ thank you for the link!!
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    (Original post by emilyp2206)
    not that i remember, the first time ive met squaring both sides was just now when looking in the textbook:/ thank you for the link!!
    imo squaring both sides is probably the better of the two methods

    we can go through some of the modulus questions if you want?

    but first, tell me, have you ever had to solve something like |z-3+4i| = |z+1-7i|? ie something with both real and imaginary parts?

    also have you been taught that z = x + iy?

    asking because I don't want to confuse you by doing too much
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    (Original post by emilyp2206)
    not that i remember, the first time ive met squaring both sides was just now when looking in the textbook:/ thank you for the link!!
    in fact how about you work through videos and if you still don't understand something feel free to tag me and ask

    Im just worried ill teach you it one way and exam solutions guy will do it a different way and you'll get confused
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    (Original post by DylanJ42)
    in fact how about you work through videos and if you still don't understand something feel free to tag me and ask

    Im just worried ill teach you it one way and exam solutions guy will do it a different way and you'll get confused
    I feel as if the whole chunk of the course from that aspect has been missed, i wil work through the videos and see how i fee! thank you for the help, i had know idea i needed this
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    (Original post by emilyp2206)
    I feel as if the whole chunk of the course from that aspect has been missed, i wil work through the videos and see how i fee! thank you for the help, i had know idea i needed this
    the videos are great and topics are explained very well so i hope they help its no problem
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    If you want some extra practice have a look at the complex number on argand diagrams section in AQA FP2
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    (Original post by DylanJ42)
    the videos are great and topics are explained very well so i hope they help its no problem
    ive through these videos but still cannot figure out how the |z|=|z-8| or any form of these type of questions occurs, the videos were useful in discussing mod of just a complex number from the origin, and then the arguments of these but not any other form (((
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    (Original post by emilyp2206)
    ive through these videos but still cannot figure out how the |z|=|z-8| or any form of these type of questions occurs, the videos were useful in discussing mod of just a complex number from the origin, and then the arguments of these but not any other form (((
    okay so say if you dont understand any of this

     \displaystyle |z| = |z-8|

    we know z = x + yi, so;

     \displaystyle |x+yi| = |x+yi -8|

    group real and imaginary groups like so;

     \displaystyle |x+yi| = |(x-8)+yi|

    Now I want you to really think about this part, ill do a diagram for you also, if you need it, square both sides;

     \displaystyle x^2 + y^2 = (x-8)^2 + y^2

     \displaystyle x^2 = x^2 -16x + 64

     \displaystyle 16x = 64

     \displaystyle x = 4

    use z = x +yi again to get in terms of z

    z = x +yi

    z = 4 +0i = 4

    so the answer to |z| = |z-8| is z = 4

    How is that?
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    (Original post by emilyp2206)
    I dont suppose anybody on here has any good resources for representing modulus and argument on argand diagrams? I feel this is the main topic holding me back in fp1

    I cant seem to get my head around my textbook (OCR)

    I cant even represent |z|=|z-8| on an argand diagram, if anyone has a worked solution to that id really appreciate it :'))
    Can you get your hands on an Edexcel FP2 textbook? It explains this stuff really nicely
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    (Original post by DylanJ42)
    okay so say if you dont understand any of this

     \displaystyle |z| = |z-8|

    we know z = x + yi, so;

     \displaystyle |x+yi| = |x+yi -8|

    group real and imaginary groups like so;

     \displaystyle |x+yi| = |(x-8)+yi|

    Now I want you to really think about this part, ill do a diagram for you also, if you need it, square both sides;

     \displaystyle x^2 + y^2 = (x-8)^2 + y^2

     \displaystyle x^2 = x^2 -16x + 64

     \displaystyle 16x = 64

     \displaystyle x = 4

    use z = x +yi again to get in terms of z

    z = x +yi

    z = 4 +0i = 4

    so the answer to |z| = |z-8| is z = 4

    How is that?
    thst makes alot of sense thank you! if you could represent this on a diagram that would be ace
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    (Original post by aymanzayedmannan)
    Can you get your hands on an Edexcel FP2 textbook? It explains this stuff really nicely
    Im pretty sure my teacher brings one of the sort to lessons sometimes so i will ask her for a peak, cheers!
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    (Original post by emilyp2206)
    thst makes alot of sense thank you! if you could represent this on a diagram that would be ace
    Name:  fp2.jpg
Views: 39
Size:  102.8 KB

     \displaystyle |(x-8)+yi| ^2 = (x-8)^2 + y^2

    so everytime you have something of the form

     \displaystyle |(z+a) + bi| \:\text{then to square it just think of pythagoras',}

     \displaystyle \text{so}\: |(z+a) + bi|^2 =(z+a)^2 + b^2

    one last thing, notice the "i" doesnt get squared or anything, as it is pretty much just telling you b units vertically.

    last last thing i promise, sketching these until you get comfortable with them might be a nice idea also, but ill leave that up to you

    Hope this helps
 
 
 
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