x Turn on thread page Beta
 You are Here: Home >< Maths

# FP1 Complex Numbers watch

1. My problem has been solved.
2. (Original post by chemistryboi)
another method that is more efficient
Consider the arg of 1+i, and what happens when you to the arg when you raise the number to the power of 4.
3. (Original post by ghostwalker)
Consider the arg of 1+i, and what happens when you to the arg when you raise the number to the power of 4.
im not sure, i^4 is equal to 1. I am without a clue on this
4. (Original post by chemistryboi)
im not sure, i^4 is equal to 1. I am without a clue on this
Ok, have you come across "arg", or the format for a complex number?
5. (Original post by ghostwalker)
Ok, have you come across "arg", or the format for a complex number?
I have not come across that format, my understanding of the argument is the angle (usually called theta) in radians measured anticlockwise from y=0 to the line Z
6. (Original post by chemistryboi)
I have not come across that format, my understanding of the argument is the angle (usually called theta) in radians measured anticlockwise from y=0 to the line Z
How about the format, and what happens when you raise it to a power?
7. (Original post by ghostwalker)
How about the format, and what happens when you raise it to a power?
I don't know where I have gotten this idea from but does it rotate? As in change quadrant but with a different angle
8. (Original post by ghostwalker)
Ok, have you come across "arg", or the format for a complex number?
This is an FP2 formula.

(Original post by chemistryboi)
Hi TSR
hence show that ((2+3i)/(5+i))^4 is real and determine its value.
You know what (2+3i)/(5+i) simplifies to, just raise that to the power 4. I.E (lambda(1+i))^4 = (lambda)^4(1+i)^4
9. (Original post by chemistryboi)
I don't know where I have gotten this idea from but does it rotate? As in change quadrant but with a different angle
It does "rotate". When you multply two complex numbers together you sum their angles, so to speak.

But since you've not come across these format yet (they are covered at A-level). I suggest substitute your expression , and square it, and square it again, to get the fourth power. After the first squaring, it will be a simpler format.
10. (Original post by ghostwalker)
.
Thank you for helping me out on this one. I greatly appreciate it.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 31, 2015
Today on TSR

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams