How do you add (9+i)+(1+3i) in trigonometric form?

1 Answer
Jul 9, 2018

10+4i

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=92+12)=82
r2=12+32=10

θ1=tan1(19)173.66, II quadrant
θ2=tan1(31)108.43, II quadrant

z1+z2=82cos(173.66)+10cos(108.43)+i(82sin173.66+10sin108.43)

91+i(1+3)

10+4i