Write the Complex Number in Rectangular Form $9 \left( \cos 180 ^ { \circ } + \mathrm { i } \sin 180 ^ { \circ } \right)$

question 400

Multiple Choice

Write the complex number in rectangular form.
- $9 \left( \cos 180 ^ { \circ } + \mathrm { i } \sin 180 ^ { \circ } \right)$

• A) \(9 \mathrm { i }\)
• B) 9
• C) \(- 9\)
• D) \(- 9 \mathrm { i }\)

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