How Do You Prove DeMoivre's Theorem for Complex Numbers?

In summary, complex numbers are numbers that can be written in the form a + bi, where a and b are real numbers and i is the imaginary unit. They are used to represent quantities that do not have a real number solution and have applications in fields such as engineering, physics, and economics. The difference between real and complex numbers is that real numbers can be plotted on a number line, while complex numbers include both real and imaginary components and cannot. Adding and subtracting complex numbers involves adding and subtracting their real and imaginary parts separately, while multiplying can be done using the FOIL method. Division can be done using long division or the conjugate method.
  • #1
lostNfound
12
0
I think I got it
 
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  • #2
Start by writing (1+i)n in trigonometric form.

What theorem do you have about raising a complex number in trigonometric form to the nth power?
 
  • #3
I think I got it
 
Last edited:
  • #4
LCKurtz said:
Start by writing (1+i)n in trigonometric form.

What theorem do you have about raising a complex number in trigonometric form to the nth power?

lostNfound said:
I did try putting (1+i)^n in trigonometric form and I got the following:
2^(n/2)*(cos(45*n)+i*sin(45*n))

OK. Now what about the answer to my question? What theorem do you have...? Look in your book.
 
  • #5
DeMoivre' Thm
 
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FAQ: How Do You Prove DeMoivre's Theorem for Complex Numbers?

What is a complex number?

A complex number is a number that can be written in the form a + bi, where a and b are real numbers and i is the imaginary unit, equal to the square root of -1. Complex numbers are used to represent quantities that do not have a real number solution, such as the square root of a negative number.

What is the difference between a real number and a complex number?

Real numbers are numbers that can be represented on a number line, including both positive and negative numbers. Complex numbers, on the other hand, include both real and imaginary components and cannot be plotted on a number line.

How do you add and subtract complex numbers?

To add or subtract complex numbers, you can simply add or subtract the real and imaginary parts separately. For example, to add (3+4i) and (5+2i), you would add 3+5=8 and 4+2=6, resulting in (8+6i).

How do you multiply and divide complex numbers?

To multiply complex numbers, you can use the FOIL method, just as you would with binomials. For example, to multiply (3+4i) and (5+2i), you would have (3+4i)(5+2i) = 15+6i+20i+8i^2 = 15+6i+20i-8 = 7+26i. To divide complex numbers, you can perform long division or use the conjugate method.

What is the application of complex numbers in real life?

Complex numbers have many applications in real life, including in engineering, physics, and economics. They are used to model and solve problems that involve alternating currents, resonance, and fluid dynamics, among others. They are also used in the fields of signal processing, control systems, and quantum mechanics.

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