MI 4 Complex Practice Exam
Name __________________________
You may use a TI-30 calculator on this exam.
True and False
_____ 1. 18cis 180 has six 6th roots in the set of complex numbers, none of which are real.
_____ 2. The complex conjugate of 2 cis(40) is 2 cis( 40) .
 
 3 
_____ 3. The complex number 4  4i can be written 4 2 cis 
 or 4 2 cis 
 4
 4 

.

_____ 4.  2cis 2   8cis8.
3
1 
 1
5. Calculate 

i
2 
 2
2012
. Put your answer in rectangular form.
6. Let z1  12cis40 and z2  3cis10 . Find the following. State your answers in polar form.
a) z12
b) z1 ·z2
c) z1 / z22
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MI 4 Complex Practice Exam
7. One of the solutions to the equation z 4  7  24i is 1  2i . With this information, graph all
four roots on the grid below.
8.
Convert each rectangular representation into its corresponding cis representation:
 3  3i
a.
b.
2i  3
9.
Convert each cis representation into its corresponding rectangular representation:
a.
4cis(45 )
b.
6 2 cis(150o)
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MI 4 Complex Practice Exam
10. Find a complex number that you can multiply z with so that z gets rotated 120 degrees
clockwise, if z  2 cis(50 ) . Give your answer in rectangular form.

3 1 
 i  . Leave your answers in cis form.
11. Solve the equation z 6  64  
 2 2 
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