How do you add $(7+9i)+(2+i)$ in trigonometric form?

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Answer 1 · 2016-10-24T11:49:06

$= sqrt(181) *(cos(0.83798)+i sin(0.83798))$

It is usually easier to simplify cartesian form and then convert to trigonometric afterwards,

$(7+9i)+(2+i)$

$9+10i$

now we convert to trigonometric.

$9+10i = r*cis(theta)$

$r=sqrt(9^2+10^2)$

$r=sqrt(181)$

$theta=tan^-1(10/9)$

$theta=0.83798$

giving us,

$(7+9i)+(2+i) = sqrt(181) *cis(0.83798)$

or in expanded form,

$= sqrt(181) *(cos(0.83798)+i sin(0.83798))$

How do you add (7+9i)+(2+i)(7+9i)+(2+i) in trigonometric form?