You are Here: Home

# How to do this?

Maths and statistics discussion, revision, exam and homework help.

Announcements Posted on
Find out how cards are replacing warnings on TSR...read more 03-12-2013
1. How to do this?

I know you have to equate the real and imaginary parts of the equation...

But with 'abi' how do you know whether it is (a x bi) or (b x ai) or (abi)..

In other words, what do I equate 3a-b to and what do I equate 12 to
2. Re: How to do this?
(Original post by sabre2th1)

I know you have to equate the real and imaginary parts of the equation...

But with 'abi' how do you know whether it is (a x bi) or (b x ai) or (abi)..

In other words, what do I equate 3a-b to and what do I equate 12 to
a*bi is the same as b*ai and abi. The key is equating the real and imaginary parts of both sides of the equation.
3. Re: How to do this?
(Original post by sabre2th1)

I know you have to equate the real and imaginary parts of the equation...

But with 'abi' how do you know whether it is (a x bi) or (b x ai) or (abi)..

In other words, what do I equate 3a-b to and what do I equate 12 to
LHS real part is 0, imaginary part is ab. So you equate 3a-b to 0 and 12 to ab.
4. Re: How to do this?
(Original post by Augmented hippo)
a*bi is the same as b*ai and abi. The key is equating the real and imaginary parts of both sides of the equation.
(Original post by Lord of the Flies)
LHS real part is 0, imaginary part is ab. So you equate 3a-b to 0 and 12 to ab.
so if we had a + bi, a is the real part but bi is imaginary? Could one say 'b' on its own is real?

Thanks
5. Re: How to do this?
(Original post by sabre2th1)
so if we had a + bi, a is the real part but bi is imaginary? Could one say 'b' on its own is real?

Thanks
This is how it works:

(a part is always a real number, picture them as coefficients (real part is the "coefficient of the unit of real numbers, 1", imaginary part is the "coefficient of the unit of complex numbers, i"))
Last edited by Lord of the Flies; 16-07-2012 at 18:43.
6. Re: How to do this?
Equate real and imaginary parts.

Hint: The real part of the LHS is zero.
7. Re: How to do this?
(Original post by Lord of the Flies)
This is how it works:

(a part is always a real number, picture them as coefficients (real part is the "coefficient of the unit of real numbers, 1", imaginary part is the "coefficient of the unit of complex numbers, i"))
regarding the bold part, what do you mean with a part? btw I understand that the imaginary part is the coefficient of i..

Thanks

Equate real and imaginary parts.

Hint: The real part of the LHS is zero.
i understand now, thanks..
8. Re: How to do this?
(Original post by sabre2th1)
regarding the bold part, what do you mean with a part? btw I understand that the imaginary part is the coefficient of i..

Thanks
A complex number has a real part and an imaginary part such that

It's basic terminology!
9. Re: How to do this?
(Original post by Lord of the Flies)
A complex number has a real part and an imaginary part such that

It's basic terminology!
Thank you

## Step 2: Register

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

this is what you'll be called on TSR

2. this can't be left blank

never shared and never spammed

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. By completing the slider below you agree to The Student Room's terms & conditions and site rules

2. Slide the button to the right to create your account

You don't slide that way? No problem.

Last updated: July 19, 2012
Study resources