How do you multiply e^(( 2 pi )/ 3 i) * e^( pi/2 i ) e2π3ieπ2i in trigonometric form?

2 Answers
May 15, 2018

cos((7pi)/6)+isin((7pi)/6)=e^((7pi)/6i)cos(7π6)+isin(7π6)=e7π6i

Explanation:

e^(itheta)=cos(theta)+isin(theta)eiθ=cos(θ)+isin(θ)

e^(itheta_1)*e^(itheta_2)==cos(theta_1+theta_2)+isin(theta_1+theta_2)eiθ1eiθ2==cos(θ1+θ2)+isin(θ1+θ2)

theta_1+theta_2=(2pi)/3+pi/2=(7pi)/6θ1+θ2=2π3+π2=7π6

cos((7pi)/6)+isin((7pi)/6)=e^((7pi)/6i)cos(7π6)+isin(7π6)=e7π6i

May 15, 2018

The answer is ==-sqrt3/2+1/2i==32+12i

Explanation:

Another method .

i^2=-1i2=1

Euler's relation

e^(itheta)=costheta+isinthetaeiθ=cosθ+isinθ

Therefore,

e^(2/3pii)*e^(pi/2i)=(cos(2/3pi)+isin(2/3pi))(cos(pi/2)+isin(pi/2))e23πieπ2i=(cos(23π)+isin(23π))(cos(π2)+isin(π2))

=(1/2+isqrt3/2)(0+i)=(12+i32)(0+i)

=1/2i-sqrt3/2=12i32

=-sqrt3/2+1/2i=32+12i