Complex numbers in the form a+bi

In summary, the conversation discusses solving the equation 1/z=(-4+4i), with the individual asking for help because they keep getting the wrong answer. They provide their attempted solution, which is correct but they are unsure why it is marked as wrong. The expert clarifies that the solution needs to be written in the form a+bi, where a and b are real numbers. The individual realizes their mistake and thanks the expert for their help.
  • #1
53Mark53
52
0

Homework Statement



How would I go about solving 1/z=(-4+4i)

The answer that I keep on getting is wrong

The Attempt at a Solution


[/B]
What I did

z=1/(-4+4i)x(-4-4i)/(-4-4i)

z=(-4-4i)/(16+16i-16i-16i^2)

z=(-4-4i)/32

z=-1/8-i/8

This is the answer that I got however it says that it is wrong. I am unsure what else I can do

Thanks for any help
 
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  • #2
53Mark53 said:

Homework Statement



How would I go about solving 1/z=(-4+4i)

The answer that I keep on getting is wrong

The Attempt at a Solution


[/B]
What I did

z=1/(-4+4i)x(-4-4i)/(-4-4i)

z=(-4-4i)/(16+16i-16i-16i^2)

z=(-4-4i)/32

z=-1/8-i/8

This is the answer that I got however it says that it is wrong. I am unsure what else I can do

Thanks for any help
Your result is right, but you might write it in the form ##-\frac{1}{8}- \frac{1}{8} i##
 
  • #3
ehild said:
Your result is right, but you might write it in the form ##-\frac{1}{8}- \frac{1}{8} i##
Thanks! I thought I was right, the online quiz that we have must have a mistake then
 
  • #4
Complex numbers ##z##, have to be expressed in the form ##z= a+bi##, where ##a, b##, are real numbers, this was missing in your solution, the ##"i"##
 
  • #5
chwala said:
Complex numbers ##z##, have to be expressed in the form ##z= a+bi##, where ##a, b##, are real numbers, this was missing in your solution, the ##"i"##
No, it was there. This is what the OP wrote:
z=-1/8-i/8
 
  • #6
53Mark53 said:
Thanks! I thought I was right, the online quiz that we have must have a mistake then
Maybe you should write 0.125 instead of 1/8.
 

Related to Complex numbers in the form a+bi

1. What are complex numbers?

Complex numbers are numbers that are expressed in the form of a+bi, where a and b are real numbers and i is the imaginary unit, defined as the square root of -1. These numbers are used to represent both real and imaginary quantities in mathematics and science.

2. What is the difference between real and imaginary numbers?

Real numbers are the numbers that we use in our everyday lives, such as 1, 2, 3, etc. They can be plotted on a number line and have a single value. Imaginary numbers, on the other hand, involve the use of the imaginary unit i and cannot be plotted on a number line. They are commonly used in mathematics and physics to represent quantities that cannot be expressed using real numbers.

3. How do you add and subtract complex numbers?

To add or subtract complex numbers, you simply add or subtract the real parts and the imaginary parts separately. For example, (3+5i)+(2-4i) = (3+2)+(5i-4i) = 5+i. Similarly, (3+5i)-(2-4i) = (3-2)+(5i+4i) = 1+9i.

4. How do you multiply and divide complex numbers?

To multiply complex numbers, you can use the FOIL method, just like you would with binomials. For example, (3+5i)(2-4i) = 6-12i+10i-20i^2 = 6-2i-20(-1) = 26-2i. To divide complex numbers, you can use the conjugate of the denominator to eliminate the imaginary unit in the denominator. For example, (3+5i)/(2-4i) = (3+5i)(2+4i)/(2-4i)(2+4i) = (6+12i+10i+20i^2)/(4+8i-8i-16i^2) = (6+22i+20(-1))/(4+16) = (26+22i)/20 = 13/10 + 11i/10.

5. How are complex numbers used in real life?

Complex numbers have various applications in fields such as engineering, physics, and economics. They are used to represent and analyze alternating currents in electrical circuits, model vibrations and waves, and solve differential equations. They also have applications in signal processing, control systems, and financial analysis.

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