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

1. 👍 0
2. 👎 0
3. 👁 271
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.

1. 👍 0
2. 👎 0
2. z^n = r^n cis(nθ)

1. 👍 0
2. 👎 0
posted by Steve

## Similar Questions

1. ### 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

asked by Kyle on April 18, 2016
2. ### trigonometry

1)Solve and write in standard form: 4x^2-4x+21=0 2)Find the standard form of the complex number. 8(cos pi/2 + i sin pi/2) Thanks everyone!

asked by mikey on December 3, 2012
3. ### math

write the expression -5i(1 + 3i) as a complex number in standard form.

asked by Anonymous on May 23, 2011
4. ### math

write the expression as a complex number in standard form 1+2i ----- 3-8i

asked by princess on January 3, 2009
5. ### Algebra 2

Write the Expression as a complex number in standard form. 5i(3+2i)(8+3i)

asked by Kaitlyn on September 22, 2014
6. ### MATH

Write the following expression as a complex number in standard form. 2-7i/-3+8i

asked by Emmett on August 11, 2012
7. ### Algebra

Write the expression as a complex number in standard form. (2-3i)-(6-5i)

asked by Lily on November 16, 2010
8. ### Algebra

Write the expression as a complex number in standard form. ____5____ 2- i =2+5i Did I get the right answer?

asked by Emma on March 26, 2013
9. ### Algebra 2

Write the expression as a complex number in standard form. 3-3i/4i I'm not sure about this problem, but I think the answer is -3/4i-3/4. Could anyone help me please?

asked by Jennie on December 8, 2011
10. ### Algebra 2

Write the expression as a complex number in standard form. (5-2i)-2(3+i) Please explain how to do this. I don't know how.

asked by Kiley on November 3, 2008

More Similar Questions