Monday

July 28, 2014

July 28, 2014

Posted by **annaiiz** on Wednesday, April 1, 2009 at 9:56pm.

question is: 1-2i+i^3/1+i

this is what i did:

1-2i+i(-i)/1+i

1-2i-i^2/1+i

1-2i-i(-1)/1+i

1-2i+i/1+i

1-3i/1+i*1-i/1-i

1-i-3i+3i^2/1-i+i-i^2

1-i-3i+3(-1)/1-i^2

1-i-3i-3/1-(-1)

1-4i-3/2

-2-4i/2

my answer is -2i-1

is that right?

- math help people lik really desperate!! -
**carpediem**, Wednesday, April 1, 2009 at 10:07pmBe more specific with parentheses. Does the 1+i divide into only the i^3 term? Or does it divide into 1 - 2i + i^3?

- math help people lik really desperate!! -
**Reiny**, Wednesday, April 1, 2009 at 10:32pmfrom what you showed in your work I will asssume you meant

(1-2i+i^3)/(1+i)

you messed up in your first line.

remember i^3 = i(i^2) = i(-1) = -i

so

(1-2i+i^3)/(1+i)

= (1-2i - i)/1+i)

= (1-3i)/(1+i)

now multiply top and bottom by 1-i to get

(1-4i - 3i^2)/(1 - i^2)

= (4-4i)/2

= 2 - 2i

**Related Questions**

Maths- complex numbers - Find tan(3 theta) in terms of tan theta Use the formula...

check my work please! - ok i have to divide complex numbers: question is: 1-2i+i...

Math - I am in the 5th grade and my homework tonight is about complex numbers. I...

math b - divide complex numbers: 2+3-3i^3/1-i

math-complex numbers - Sketch the sets of complex numbers in the complex plane ...

Question (PLEASE READ!!!) - What website is when you can ask any questions and ...

Math - Hot numbers in a lottery are numbers that keep coming up. Cold numbers ...

Advice on IB subjects - Hey there all! Im desperate for some advice on my ...

simple question - if i were writing a newspaper article and the title was "a ...

Math (Complex Numbers) - Let a,b,c be complex numbers satisfying a+b+c=abc=1 and...