How do you write the complex number in trigonometric form -8+3i8+3i?

1 Answer
Aug 14, 2017

The trigonometric form is =2.92 (cos(159.4^@)+isin(159.4^@))=2.92e^(159.4^@i)=2.92(cos(159.4)+isin(159.4))=2.92e159.4i

Explanation:

Our complex number is

z=-8+3iz=8+3i

The trigonometric form is

()()z=r(costheta+isintheta)z=r(cosθ+isinθ)

If our complex number is z=a+ibz=a+ib

r=|z|=sqrt(a^2+b^2)r=|z|=a2+b2

And

costheta=a/|z|cosθ=a|z| and

sintheta=b/|z|sinθ=b|z|

Therefore,

|z|=sqrt((-8)^2+3^2)=sqrt(64+9)=sqrt73=2.92|z|=(8)2+32=64+9=73=2.92

costheta=-8/sqrt73cosθ=873

sintheta=3/sqrt73sinθ=373

We are in the Quadrant IIII

Theta=159.4^@

The trigonometric form is

z=2.92 (cos(159.4^@)+isin(159.4^@))=2.92e^(159.4^@i)