Math Problem Statement

Divide (3 + 4i) by (1 + i) and write the answer in standard form.

Solution

To solve the expression 3+4i1+i\frac{3 + 4i}{1 + i}, we need to divide these complex numbers and write the result in standard form a+bia + bi, where aa and bb are real numbers.

Step-by-step solution:

  1. Multiply by the conjugate: To simplify the division, multiply both the numerator and the denominator by the conjugate of the denominator. The conjugate of 1+i1 + i is 1i1 - i. 3+4i1+i1i1i=(3+4i)(1i)(1+i)(1i)\frac{3 + 4i}{1 + i} \cdot \frac{1 - i}{1 - i} = \frac{(3 + 4i)(1 - i)}{(1 + i)(1 - i)}

  2. Simplify the denominator: Use the difference of squares formula: (1+i)(1i)=12i2=1(1)=2(1 + i)(1 - i) = 1^2 - i^2 = 1 - (-1) = 2 So, the denominator simplifies to 22.

  3. Multiply the numerator: Now, distribute (3+4i)(1i)(3 + 4i)(1 - i): 3(1i)+4i(1i)=33i+4i4i23(1 - i) + 4i(1 - i) = 3 - 3i + 4i - 4i^2 Simplifying: 33i+4i4(1)=33i+4i+4=7+i3 - 3i + 4i - 4(-1) = 3 - 3i + 4i + 4 = 7 + i

  4. Final division: Now divide the result by 22: 7+i2=72+12i\frac{7 + i}{2} = \frac{7}{2} + \frac{1}{2}i

Thus, the final answer in standard form is: 72+12ior3.5+0.5i\frac{7}{2} + \frac{1}{2}i \quad \text{or} \quad 3.5 + 0.5i

Would you like more details on any step or have any questions? Here are some related questions to explore further:

  1. What is the significance of the conjugate when dividing complex numbers?
  2. How do you multiply two complex numbers in general?
  3. What are some real-world applications of complex numbers?
  4. Can you divide complex numbers without using conjugates?
  5. How do we interpret complex numbers geometrically on the complex plane?

Tip: Always remember to rationalize the denominator by multiplying with the conjugate when dividing complex numbers.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Algebra

Formulas

(a + bi)(a - bi) = a^2 + b^2
(a + bi) ÷ (c + di) = [(a + bi)(c - di)] / (c^2 + d^2)

Theorems

Conjugate of Complex Numbers
Division of Complex Numbers

Suitable Grade Level

Grades 10-12