How do you add (82i)+(73i) in trigonometric form?

1 Answer
Jun 25, 2018

155i

Explanation:

z=a+bi=r(cosθ+isinθ)

r=a2+b2, θ=tan1(ba)

r1(cos(θ1)+isin(θ2))+r2(cos(θ2)+isin(θ2))=r1cos(θ1)+r2cos(θ2)+i(r1sin(θ1)+r2sin(θ2))

r1=82±22)=68
r2=72±32=58

θ1=tan1(28)345.96, IV quadrant
θ2=tan1(37)336.8, IV quadrant

z1+z2=68cos(345.96)+58cos(336.8)+i(68sin345.96+58sin336.8)

8+7+i(23)

155i