Friday, April 10, 2015

Determine all solutions to z^5 = root(3) + iAnswer in polar form.

Put sqrt3+i=t => z^5=t =>
z=(t)^(1/5)


Use polar form for
t:


t = r(cos theta+i sin
theta)


r=sqrt((sqrt3)^2+1^2) => r=sqrt4 =>
r=2


Use the formula to express theta: tan theta=coefficient
of i/number alone= imaginary part of complex number/real part of complex
number


tan theta=1/sqrt3 => theta=30 degrees or pi/6
radians


t=2(cos(pi/6)+isin(pi/6))


z=(2)^(1/5)*(cos(pi/6)+isin(pi/6))^(1/5)


Use
De Moivre's
theorem:


z=(2)^(1/5)*(cos(pi/6+2npi)/5+isin(pi/6+2npi)/5)



Answer:
put n=0=>z=(2)^(1/5)*(cos(pi/30)+isin(pi/30))


put
n=1=>z=(2)^(1/5)*(cos(13pi/30)+isin(13pi/30))


put
n=2=>z=(2)^(1/5)*(cos(25pi/30)+isin(25pi/30))


put
n=3=>z=(2)^(1/5)*(cos(37pi/30)+isin(37pi/30))


put
n=4=>z=(2)^(1/5)*(cos(49pi/30)+isin(49pi/30))

No comments:

Post a Comment

Film: 'Crocodile Dundee' directed by Peter FaimanHow are stereotypical roles upheld and challenged?

One of the stereotypes that is both upheld and challenged is the role of the damsel in distress. Sue is supposed to be the delic...