Math Problem Statement

Solution

To solve the given problem x2+2x=ix^2 + 2x = i, we need to find the complex solutions and determine the product of their real parts.

First, rewrite the equation as: x2+2xi=0x^2 + 2x - i = 0

To solve this quadratic equation, we use the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} where a=1a = 1, b=2b = 2, and c=ic = -i.

Substitute these values into the formula: x=2±2241(i)21x = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-i)}}{2 \cdot 1} x=2±4+4i2x = \frac{-2 \pm \sqrt{4 + 4i}}{2} x=2±4(1+i)2x = \frac{-2 \pm \sqrt{4(1 + i)}}{2} x=2±21+i2x = \frac{-2 \pm 2\sqrt{1 + i}}{2} x=1±1+ix = -1 \pm \sqrt{1 + i}

Now, let's find the square root of 1+i1 + i. To do this, we express 1+i1 + i in polar form: 1+i=2(cosπ4+isinπ4)1 + i = \sqrt{2} \left( \cos\frac{\pi}{4} + i \sin\frac{\pi}{4} \right)

Taking the square root: 1+i=2(cosπ4+isinπ4)\sqrt{1 + i} = \sqrt{\sqrt{2} \left( \cos\frac{\pi}{4} + i \sin\frac{\pi}{4} \right)} 1+i=24(cosπ8+isinπ8)\sqrt{1 + i} = \sqrt[4]{2} \left( \cos\frac{\pi}{8} + i \sin\frac{\pi}{8} \right)

In rectangular form, this can be approximated as: 1+i1.0987+0.4551i\sqrt{1 + i} \approx 1.0987 + 0.4551i

Therefore, the solutions are: x1=1+(1.0987+0.4551i)0.0987+0.4551ix_1 = -1 + (1.0987 + 0.4551i) \approx 0.0987 + 0.4551i x2=1(1.0987+0.4551i)2.09870.4551ix_2 = -1 - (1.0987 + 0.4551i) \approx -2.0987 - 0.4551i

The real parts of the solutions are approximately 0.09870.0987 and 2.0987-2.0987.

Finally, the product of their real parts is: 0.0987×2.09870.20710.0987 \times -2.0987 \approx -0.2071

Thus, the product of the real parts of the solutions is approximately 0.2071-0.2071.

Would you like more details or have any questions?

Here are some questions you might want to explore next:

  1. How do you solve a quadratic equation with complex coefficients?
  2. Can you explain the polar form of a complex number?
  3. What is the significance of the roots of a quadratic equation in complex analysis?
  4. How can we verify the solutions of a quadratic equation?
  5. What are some applications of complex numbers in engineering and physics?

Tip: When dealing with complex roots, converting complex numbers to their polar form often simplifies the calculation of roots and powers.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Complex Numbers
Quadratic Equations
Polar Form of Complex Numbers

Formulas

Quadratic formula

Theorems

-

Suitable Grade Level

Grades 10-12