Math Problem Statement

Find the graph of this function as the value of n increases, starting from n = 1. f(n) = (sqrt(3)/2 + 1/2 * i)^n

Solution

Let's analyze the mathematical function shown in the image.

The function given is:

f(n)=(32+12i)nf(n) = \left( \frac{\sqrt{3}}{2} + \frac{1}{2} i \right)^n

This is a complex number raised to the power nn. The term inside the parentheses has both a real part 32\frac{\sqrt{3}}{2} and an imaginary part 12i\frac{1}{2}i. Let's explore what happens to the function’s graph as nn increases.


Detailed Explanation

  1. The Complex Base
    The number inside the parentheses, 32+12i\frac{\sqrt{3}}{2} + \frac{1}{2}i, is in the form a+bia + bi, where a=32a = \frac{\sqrt{3}}{2} and b=12b = \frac{1}{2}. This corresponds to a point in the complex plane.

    • Polar form:
      The complex number’s magnitude (modulus) is:

      z=(32)2+(12)2=34+14=1=1|z| = \sqrt{ \left(\frac{\sqrt{3}}{2}\right)^2 + \left(\frac{1}{2}\right)^2 } = \sqrt{\frac{3}{4} + \frac{1}{4}} = \sqrt{1} = 1

      The argument (angle with the positive real axis) is:

      θ=tan1(1232)=tan1(13)=π6\theta = \tan^{-1}\left(\frac{\frac{1}{2}}{\frac{\sqrt{3}}{2}}\right) = \tan^{-1}\left(\frac{1}{\sqrt{3}}\right) = \frac{\pi}{6}

  2. Effect of Raising to Power nn
    In polar form, raising a complex number z=reiθz = r e^{i\theta} to the power nn results in:

    zn=rneinθz^n = r^n e^{in\theta}

    Since r=1r = 1, the magnitude stays 1 for all nn. Thus, only the angle changes as nn increases. Specifically:

    New angle=nπ6\text{New angle} = n \cdot \frac{\pi}{6}

    This means each time nn increases by 1, the point rotates by π6\frac{\pi}{6} radians (or 30 degrees) counterclockwise on the unit circle.

  3. Graph Description
    As shown in the provided images:

    • The blue points mark the position of f(n)f(n) on the unit circle for increasing values of nn.
    • For n=1n = 1, the point is at an angle π6\frac{\pi}{6}.
    • For n=2n = 2, it moves to 2π6=π32 \cdot \frac{\pi}{6} = \frac{\pi}{3}, and so on.
    • As nn grows, the point continues to rotate around the circle in steps of 30 degrees.

Conclusion

The function f(n)=(32+12i)nf(n) = \left(\frac{\sqrt{3}}{2} + \frac{1}{2} i\right)^n traces points along the unit circle, rotating counterclockwise by 3030^\circ for each increment of nn. The red arrow likely shows the direction of rotation, and the blue points mark the positions after each step.


Do you need any further details or explanations?

Here are five related questions to deepen your understanding:

  1. What is the difference between polar and Cartesian representations of complex numbers?
  2. How do you convert between polar form and rectangular form of a complex number?
  3. What happens if the magnitude rr were not 1 in this case?
  4. Can you generalize how rotations work for other angles in complex numbers?
  5. How does complex multiplication affect the magnitude and angle of the product?

Tip:
Always try expressing complex functions in polar form when dealing with powers, as it simplifies understanding rotations and magnitudes!

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Polar Coordinates
Powers of Complex Numbers

Formulas

Complex Number Magnitude |z| = sqrt(a^2 + b^2)
Complex Number Argument theta = tan^(-1)(b/a)
Raising Complex Number to Power: z^n = r^n * e^(in*theta)

Theorems

Euler's Formula: e^(ix) = cos(x) + i*sin(x)
Multiplication Theorem for Complex Numbers in Polar Form

Suitable Grade Level

Grades 11-12 or Introductory College Level