# Trigonometry

Write each expression in the standard form for a complex number, a + bi.
A. [3(cos(27°)) + isin(27°)]^5
B. [2(cos(40°)) + isin(40°)]^6
For A i got 2.67+1.36i and for B i got 1.53+1.29i

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1. (3cis27°)^5
= 3^5 cis135°
= 243 (1/√2 - 1/√2 i)

(2cis40°)^6
= 2^6 cis240°
= 64 (-1/2 - √3/2 i)

you can make those into a+bi form, but you need to review deMoivre's formulas

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posted by Steve

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