Math Problem Statement

(1+i)^12

Solution

To compute (1+i)12(1 + i)^{12}, we can use De Moivre's Theorem. Here’s a step-by-step process to solve it:

Step 1: Express 1+i1 + i in polar form.

  1. Magnitude of 1+i1 + i:
    r=1+i=12+12=2r = |1 + i| = \sqrt{1^2 + 1^2} = \sqrt{2}

  2. Argument (angle θ\theta):
    Since 1+i1 + i is in the first quadrant, the argument is: θ=tan1(11)=π4\theta = \tan^{-1}\left(\frac{1}{1}\right) = \frac{\pi}{4} So, 1+i1 + i in polar form is: 1+i=2cis(π4)1 + i = \sqrt{2} \text{cis} \left(\frac{\pi}{4}\right) (where cis(θ)\text{cis}(\theta) stands for cos(θ)+isin(θ)\cos(\theta) + i\sin(\theta)).

Step 2: Use De Moivre’s Theorem

De Moivre’s Theorem states: (rcisθ)n=rncis(nθ)(r \text{cis} \theta)^n = r^n \text{cis} (n \theta) So for (1+i)12(1 + i)^{12}, we have: (2cisπ4)12=(2)12cis(12π4)(\sqrt{2} \text{cis} \frac{\pi}{4})^{12} = (\sqrt{2})^{12} \text{cis} \left(12 \cdot \frac{\pi}{4}\right)

Step 3: Simplify the expression

  1. Magnitude: (2)12=(21/2)12=26=64(\sqrt{2})^{12} = (2^{1/2})^{12} = 2^6 = 64

  2. Argument: 12π4=3π12 \cdot \frac{\pi}{4} = 3\pi Since cis(3π)=cos(3π)+isin(3π)=1+0i\text{cis}(3\pi) = \cos(3\pi) + i\sin(3\pi) = -1 + 0i, we have: cis(3π)=1\text{cis}(3\pi) = -1

Step 4: Final Answer

Thus, (1+i)12=64(1)=64(1 + i)^{12} = 64 \cdot (-1) = -64

So, (1+i)12=64(1 + i)^{12} = -64.

Would you like more details or have any questions?

Related Questions:

  1. What is De Moivre's Theorem and how does it apply to complex numbers?
  2. How do you convert a complex number from rectangular to polar form?
  3. What are the properties of powers of complex numbers?
  4. How can you compute (1i)12(1 - i)^{12} using a similar method?
  5. What happens when you apply De Moivre's theorem for non-integer powers?

Tip: When converting complex numbers to polar form, remember to carefully determine the argument based on the quadrant of the complex number.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Polar Coordinates
Exponentiation of Complex Numbers

Formulas

Polar form of a complex number: z = r(cosθ + i sinθ)
De Moivre's Theorem: (r cis θ)^n = r^n cis(nθ)

Theorems

De Moivre's Theorem

Suitable Grade Level

Grades 11-12 and Early College