Turn on thread page Beta
    • Thread Starter
    Offline

    7
    ReputationRep:
    z = a+bi
    z^2 = c+di

    prove that a^2=1/2(c+sqrt(c^2+d^2))
    • Community Assistant
    • Very Important Poster
    Offline

    20
    ReputationRep:
    Community Assistant
    Very Important Poster
    (Original post by intesar)
    z = a+bi
    z^2 = c+di

    prove that a^2=1/2(c+sqrt(c^2+d^2))
    As z=a+bi, it follows that z^2=(a+bi)^2.

    But you also know that z^2=c+di

    So you two expressions which are equal to z^2. Equate them and make a^2 the subject.
    Offline

    20
    ReputationRep:
    you need to equate the real parts and then the imaginary parts of ( a + bi )2 and c + di
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 7, 2016
The home of Results and Clearing

2,738

people online now

1,567,000

students helped last year

University open days

  1. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  3. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
Poll
A-level students - how do you feel about your results?
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.