Trigonometry Help please

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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asked by Kyle
  1. (De Moivre's Theorem) Let z = r(cosθ + i sinθ)^n, and let n be a positive integer. Then zn = rn(cos nθ + i sin nθ) 1 Page 2 (i.e. in taking the nth power of z, we raise the modulus to its nth power and multiply the argument by n.)

    So I will do one.
    A. [3(cos(27°)) + isin(27°)]^5
    [15(cos(5*27°)) + i5*sin(5*27°)] =
    10.6+i 3.54

    check that.

  2. z^n = r^n cis(nθ)

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    posted by Steve

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