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How do you calculate √(3+i)?

2 Answers

5 votes

Answer:

To calculate the square root of a complex number like \(3+i\), you can use the following steps:

1. **Express the Complex Number in Polar Form:**

- Find the polar form of the complex number \(3+i\). The polar form is given by:

\[ r(\cos \theta + i \sin \theta) \]

- Calculate the magnitude \(r\) and the argument \(\theta\).

The magnitude \(r\) is given by:

\[ r = \sqrt{a^2 + b^2} \]

where \(a\) and \(b\) are the real and imaginary parts of the complex number.

For \(3 + i\), \(a = 3\) and \(b = 1\), so:

\[ r = \sqrt{3^2 + 1^2} = \sqrt{10} \]

The argument \(\theta\) is given by:

\[ \theta = \arctan\left(\frac{b}{a}\right) \]

For \(3 + i\), \(\theta = \arctan\left(\frac{1}{3}\right)\).

2. **Apply the Square Root Formula:**

- Once you have the polar form, use the square root formula:

\[ \sqrt{r}(\cos \frac{\theta}{2} + i \sin \frac{\theta}{2}) \]

For \(3+i\), the square root is:

\[ \sqrt{\sqrt{10}}\left(\cos \frac{\arctan\left(\frac{1}{3}\right)}{2} + i \sin \frac{\arctan\left(\frac{1}{3}\right)}{2}\right) \]

Use a calculator to approximate the values.

This process involves converting the complex number into polar form and then applying the square root formula in polar coordinates. The result will be the square root of the given complex number.

User JessieArr
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Final answer:

To calculate the square root of (3+i), use the formula for the square root of a complex number in rectangular form. Solve the equations simultaneously to find the real and imaginary parts of the square root.

Step-by-step explanation:

To calculate the square root of (3+i), we can use the formula for the square root of a complex number in rectangular form. Let's assume that √(3+i) = a+bi, where a and b are real numbers. We can square both sides of this equation to find:

3+i = (a+bi)^2 = a^2 + 2abi - b^2

Comparing the real and imaginary parts of this equation, we get two equations:

1) 3 = a^2 - b^2

2) 1 = 2ab

Solving these equations simultaneously will give us the values for a and b, which will be the real and imaginary parts of the square root of (3+i).

From equation 2), we can conclude that ab = 1/2. From equation 1), we have:

3 = a^2 - (1/2a)^2 = a^2 - 1/4a^2 = 3/4a^2

Simplifying, we get:

a^2 = 4

a = 2 or a = -2

Substituting a = 2 into equation 2), we get b = 1/4. So one solution is a+bi = 2 + (1/4)i.

Substituting a = -2 into equation 2), we get b = -1/4. So another solution is a+bi = -2 + (-1/4)i.

Therefore, √(3+i) can be either 2 + (1/4)i or -2 + (-1/4)i.

User Zsubzwary
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