How do you add (2+3i)+(6+i) in trigonometric form?

1 Answer
Jun 25, 2018

(2+3i)+(6+i)=4+4i=4(1+i)

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=22+32)=13
r2=62±12=37

θ1=tan1(32)123.69, II quadrant
θ2=tan1(16)9.4623, I quadrant

z1+z2=13cos(123.69)+37cos(9.4623)+i(13sin(123.69)+37sin(9.4623))

2+6+i(3+1)
4+4i

Proof:

2+3i+6+i

4+4i