Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    Hi,

    http://pmt.physicsandmathstutor.com/...%20Edexcel.pdf

    On Q6 on the link above, I got up to the point where:
    3|w-1| = |wi|

    I don't understand why it is valid to cancel the i on the right hand side as the author of the model answers has done, and feel as though I have a gap in my knowledge.
    I'm aware leaving the i in will lead to some difficulty later on, but I can't work out why it is valid to just remove it.

    Thanks in advance.
    Offline

    11
    ReputationRep:
    Standard rule |Z1 x Z2| = |Z1| x |Z2|

    |wi| = |w| x |i| = |w|
    Offline

    14
    ReputationRep:
    (Original post by JLegion)
    Hi,

    http://pmt.physicsandmathstutor.com/...%20Edexcel.pdf

    On Q6 on the link above, I got up to the point where:
    3|w-1| = |wi|

    I don't understand why it is valid to cancel the i on the right hand side as the author of the model answers has done, and feel as though I have a gap in my knowledge.
    I'm aware leaving the i in will lead to some difficulty later on, but I can't work out why it is valid to just remove it.

    Thanks in advance.
     \left |0 + iw  \right | = \sqrt{0^2 + w^2} =w
    • Community Assistant
    Offline

    18
    ReputationRep:
    Community Assistant
    (Original post by JLegion)
    Hi,

    http://pmt.physicsandmathstutor.com/...%20Edexcel.pdf

    On Q6 on the link above, I got up to the point where:
    3|w-1| = |wi|

    I don't understand why it is valid to cancel the i on the right hand side as the author of the model answers has done, and feel as though I have a gap in my knowledge.
    I'm aware leaving the i in will lead to some difficulty later on, but I can't work out why it is valid to just remove it.

    Thanks in advance.
    |i| = 1 it could have been shown using another step |i|\times|w|, but I guess he just wanted to safe space.
    • Thread Starter
    Offline

    2
    ReputationRep:
    Thank you everyone for the swift replies.

    I feel stupid not to know that; although in my defence my text book doesn't mention it once! ^.^

    Thanks again.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 18, 2017
Poll
Do you think parents should charge rent?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.