Help Needed: Solve Cube Root Question ASAP

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    Cube Root
Using this formula three times, you can find the three cube roots in polar form. Once you have the three roots in polar form, you can convert them into modulus-argument form by simply taking the magnitude and argument of each root. The principal root will be the one with the smallest argument. In summary, to determine the three cube roots of (3 - i)/(3 + i) in modulus-argument form, first calculate the polar form of the complex fraction, then use DeMoivre's Formula to find the three roots in polar form, and finally convert them into modulus-argument form and identify the principal root.
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whooi
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can someone help me solve this question as fasd as possible??
im really headache wif it...
thx~~

determine the 3 cube roots of 3-i over 3+i giving the result in modulus argument form,express the principal root in the form a+Jb
 
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hello..anyone can help me out??
 
  • #3
whooi said:
can someone help me solve this question as fasd as possible??
im really headache wif it...
thx~~

determine the 3 cube roots of 3-i over 3+i giving the result in modulus argument form,express the principal root in the form a+Jb

Do not bump your post after only 16 minutes. It is unreasonable to expect fast help all the time here on the PF.

Also, you must show your attempt at a solution before we can be of help. Show us how you would go about simplifying the complex fraction that you are describing...
 
  • #4
First off, you're going to want to calculate (3 - i)/(3 + i), to get it in the form a + bi. After that, you should calculate the polar form of this complex number, r(cos[itex]\theta[/itex] + i sin[itex]\theta[/itex]). After that, you can use DeMoivre's Formula to find a cube root, which says that
[tex](r(cos\theta + i sin\theta))^{1/n} = r^{1/n}(cos(\theta/n) + i sin(\theta/n))[/tex].
 

1. How do you solve a cube root question?

To solve a cube root question, you need to find the number that, when multiplied by itself three times, gives you the original number. This can be done by using a calculator or by factoring the number into its prime factors and identifying the number that appears three times.

2. What is the formula for solving a cube root?

The formula for solving a cube root is:
cube root of x = x^(1/3)

3. Can you give an example of solving a cube root question?

For example, if we want to find the cube root of 27, we can use the formula:
cube root of 27 = 27^(1/3)
Therefore, the answer is 3, as 3 x 3 x 3 = 27.

4. How do we know if a number has a rational or irrational cube root?

If a number's cube root can be expressed as a fraction of two integers (e.g. 1/2, 2/3, 3/4), then it is a rational cube root. If the number cannot be expressed as a fraction, it is an irrational cube root.

5. Can cube root questions have negative answers?

Yes, cube roots can have negative answers. This is because a negative number multiplied by itself three times can still result in a negative number. For example, the cube root of -8 is -2, as -2 x -2 x -2 = -8.

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