Quest Review 6.5 Trig Form of a Complex Number
A
Name ___________________________
1. Graph 2 – 3i and find the absolute value. No decimals.
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2. Write 3  3i in trigonometric form.
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3. Write 6(cos 150  i sin 150) in exact complex form.
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4. If z1 = 4(cos70  i sin70) and z2 = 9(cos20  i sin20) ,
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find z1 z2 . Write your answer in exact complex form.


5. If z1  15  cos
3π
3π 



 i sin  and z2  2.5  cos  i sin  ,
2
2 
3
3

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find z1 / z2 . Write your answer in exact complex form.
6. Find  5  cos60  i sin60 

4

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Write your answer in complex form.

7. Find 2  2 3 i

6
Write your answer in exact complex form.
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8. Find the cubic roots of 27cos60  i sin60
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Write answers in trigonometric form.
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9. Find the fourth roots of 5  5i .
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Write answers in complex form approximated to two decimal places.
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10. Solve the equation for all possible roots: x6  64
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Write answers in trigonometric form.
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11. Given u  2, 3 and v  3, 6 , find the projection of u onto v.
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12. Find the vector component of u orthogonal to v.
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