Question:

Express the given complex number in the form\( a + ib: (-2-\dfrac{1}{3}i)^3\)

Updated On: Oct 18, 2023
Hide Solution
collegedunia
Verified By Collegedunia

Solution and Explanation

\((-2-\dfrac{1}{3}i)^3\)

\(=-[2^3+(\dfrac{i}{3})^3+3.(2)(\dfrac{i}{3})(2)(2+\dfrac{i}{3})]\)

\(=-[8+\dfrac{i^3}{27}+2i(2+\dfrac{i}{3})]\)

\(=-[8-\dfrac{i}{27}+4i-\dfrac{2}{3}]\)

\(=-[\dfrac{22}{7}+\dfrac{107}{27}i]\)

\(=-\dfrac{22}{3}-\dfrac{107}{27}i\)  (Ans.)

Was this answer helpful?
0
0

Concepts Used:

Complex Numbers and Quadratic Equations

Complex Number: Any number that is formed as a+ib is called a complex number. For example: 9+3i,7+8i are complex numbers. Here i = -1. With this we can say that i² = 1. So, for every equation which does not have a real solution we can use i = -1.

Quadratic equation: A polynomial that has two roots or is of the degree 2 is called a quadratic equation. The general form of a quadratic equation is y=ax²+bx+c. Here a≠0, b and c are the real numbers.