Question
Practice
- Convert each number to polar form and evaluate:
- Find the cube roots of:
(a) 125 j
(a) 125 j
Ask by Willis Horton. in South Africa
Mar 21,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
To convert each complex number to polar form, use
, where
and
. Then, evaluate the given expressions accordingly.
Solution
To convert a complex number to polar form, we use the formula
, where
is the magnitude of the complex number and
is the angle it makes with the positive real axis.
Given the complex numbers:
(a)
(b)
©
(d)
(a)
(b)
©
(d)
We will convert each complex number to polar form and then evaluate the given expressions.
Let’s start with the first complex number:
(a)
(a)
The magnitude
is given by
, where
is the real part and
is the imaginary part. In this case,
and
.
The angle
is given by
. In this case,
.
Now, we can express
in polar form as
.
Let’s calculate the values of
and
for the other complex numbers and then evaluate the given expressions.
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The Deep Dive
To convert numbers to polar form, you first find the magnitude and angle (argument) of the complex numbers involved. For instance, for
, the magnitude is
and the argument
.
Now let’s dive into the cube roots of
. This number can be expressed in polar form as
(magnitude) and an angle of
(since it’s purely imaginary). The cube roots can be found by using the formula:
for
. Thus, each cube root can be calculated from there!
Now, for a bit more context: The history of polar form stems from the desire to simplify complex number operations, particularly multiplication and division, which can be done through magnitudes and angles instead of wrestling with real and imaginary parts.
And if you’re looking for practical advice, always remember: when adding or subtracting complex numbers, it’s best to combine like terms first. Many mistakes arise when people forget to handle the real and imaginary parts separately!