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9.3 Complex Numbers; The Complex Plane; Polar Form of Complex Numbers. In a complex number. a is the real part and bi is the imaginary part. When b=0, the complex number is a real number. When a 0 , and b 0, as in 5+8i, the complex number is an imaginary number.
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9.3Complex Numbers; The Complex Plane;Polar Form of Complex Numbers
In a complex number a is the real part and bi is the imaginary part. When b=0, the complex number is a real number. When a0, and b0, as in 5+8i, the complex number is an imaginary number. When a=0, and b0, as in 5i, the complex number is a pure imaginary number.
The Complex Plane Imaginary Axis Real Axis O
Let be a complex number. The magnitude or modulus of z, denoted by is defined As the distance from the origin to the point (x, y).
Imaginary Axis y |z| Real Axis O x
Imaginary Axis 4 z =-3 + 4i Real Axis -3
z = -3 + 4i is in Quadrant II x = -3 and y = 4
z =-3 + 4i 4 Find the reference angle () by solving -3
z =-3 + 4i 4 -3
Imaginary Axis 4 Real Axis -3
Find the cosine of 330 and substitute the value. Find the sine of 330 and substitute the value. Distribute the r
Find the complex fifth roots of The five complex roots are: for k = 0, 1, 2, 3,4 .
The roots of a complex number a cyclical in nature. That is, when the points are plotted on a polar plane or a complex plane, the points are evenly spaced around the origin
To find the principle root, use DeMoivre’s theorem using rational exponents. That is, to find the principle pth root of Raise it to the power
Example You may assume it is the principle root you are seeking unless specifically stated otherwise. Find First express as a complex number in standard form. Then change to polar form
Since we are looking for the cube root, use DeMoivre’s Theorem and raise it to the power
Example: Find the 4th root of Change to polar form Apply DeMoivre’s Theorem