Complex numbers

(a)   of a complex number is found by reversing the algebraic sign of the complex numbers imaginary number only while keeping the algebraic sign of the real number the same.

What complex number is represented by the graph?

• -3-i
• -3+i
• 1+3i
• 1-3i

• 15

• -15

• 15i

• -15i 

• A
• B
• C
• D

Express 2 cis (4π/3) in the form x + yi

Express z = 1-i in polar form

• r = sqrt(2), theta = -45 degrees
• r = sqrt(2), theta = 45 degrees
• r = 2, theta = -45 degrees
• r = 2, theta = 45 degrees

Answer explanation

 $WRITE\ IN\ TRIGONOMETRIC\ FORM:\ \ \$   $-1\ +i$  

•  $\left(\sqrt{2}\left(\cos\left(\frac{1}{4}\pi\right)\right)\ +\ i\ \sin\ \left(\frac{1}{4}\pi\right)\right)$  

•  $\sqrt{2}\left(\cos\ \frac{3}{4}\pi\ +i\ \sin\ \frac{3}{4}\pi\right)$  

•  $\sqrt{3}\left(\sin\ \frac{1}{4}\pi+\ \cos\ \frac{1}{4}\pi\right)$  

•  $\sqrt{2}\left(\cos\ \frac{5}{4}\pi\ +\ \sin\ \frac{5}{4}\pi\right)$  

Write the complex number in Polar Form. Express the argument:    6+0i

Answer explanation