You are Here: Home >< Maths

# Converting to a+jb form

Announcements Posted on
Why bother with a post grad? Are they even worth it? Have your say! 26-10-2016
1. I'm having problems with this, the annoying thing is I've done it, however I can't remember how I did the previous example or I have changed the mode on my calculator and it's destroyed what I was doing.

I have to convert this;

2.4 /_ -(π/6)

So I have;

a= r cos ϴ = 2.4 cos -30 = ???

b= r sin ϴ = 2.4 sin -30 = ???

I input it into my casio and just comes up with maths error, I changed my calculator to radians and then back and now I don't know why I can't do this.

So if someone could walk me through it would be great, cheers.
2. (Original post by Brainfrozen)
I'm having problems with this, the annoying thing is I've done it, however I can't remember how I did the previous example or I have changed the mode on my calculator and it's destroyed what I was doing.

I have to convert this;

2.4 /_ -(π/6)
I don't know that that is...

So I have;

a= r cos ϴ = 2.4 cos -30 = ???

b= r sin ϴ = 2.4 sin -30 = ???

I input it into my casio and just comes up with maths error, I changed my calculator to radians and then back and now I don't know why I can't do this.

So if someone could walk me through it would be great, cheers.
You should really know off the top of your head that cos(-30) = sqrt(3)/2 and sin(-30) = -1/2.

Anywho, if you're sure you're in degree mode then trying doing 2.4 sin (-30), i.e: explicitly use the bracket
3. (Original post by Zacken)
I don't know that that is...

You should really know off the top of your head that cos(-30) = sqrt(3)/2 and sin(-30) = -1/2.

Anywho, if you're sure you're in degree mode then trying doing 2.4 sin (-30), i.e: explicitly use the bracket
I have no idea what's gone wrong, tried it on my work's calculator and it works fine. I've clearly changed something in the calculator and it's not working.
4. (Original post by Brainfrozen)
I have no idea what's gone wrong, tried it on my work's calculator and it works fine. I've clearly changed something in the calculator and it's not working.
If you've got a casio, try pressing mode and then clearing your settings.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: September 19, 2016
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:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams