Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter

    I'm stuck on the second part of this question, please give me hints and clues in the right direction
    Given that z1 = 12 + 5j and z2 = -3 + 4j, verify that |z1 + z2| is less than/equal to |z1| + |z2|. I managed this part and got 12.73 < 18.
    This is the part I don't know how to do:
    Explain geometrically using an Argand diagram why |z1 + z2| is less than/equal to |z1| + |z2| is always true.
    Any help would be greatly appreciated!!

    |z1|+|z2| can only be equal to|z1+z2| If they are multiples of each other( in other words they have the same argument). If they are not multiples (have different arguments) then |z1|+|z2| is greater than |z1+z2|.
    I advise you to draw an argand diagram and draw these 2 cases and realise why this is the case.

    draw the vectors for Z1 and Z2 nose to tail... then complete the triangle; this will be vector Z1 + Z2

    Pretty sure it's an application of a triangle rule( the sum of one side is equal to or less than the sum of the other two sides)

    Posted from TSR Mobile
Have you ever experienced racism/sexism at uni?
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here


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