## anonymous one year ago Write the following complex number in polar form. Express all angles in degrees rounded to the nearest tenth. –3

1. zepdrix

$\Large\rm -3=\color{royalblue}{3}\cdot\color{orangered}{(-1)}=\color{royalblue}{r}\cdot\color{orangered}{e^{i?}}$

2. zepdrix

You have learned about the exponential form, or no?

3. zepdrix

$\large\rm \color{royalblue}{3}\cdot\color{orangered}{(-1)}=\color{royalblue}{r}\color{orangered}{(\cos \theta+i \sin \theta)}$Maybe this breakdown is unnecessary. -3 is along the real axis. So what angle is that? :)

4. zepdrix

|dw:1441669382809:dw|

5. anonymous

yes, i know what exponential form. the angle would be 180 degrees, yes? but how do i write the entire answer?

6. zepdrix

|dw:1441670191367:dw|$\large\rm \color{royalblue}{r}\color{orangered}{(\cos \theta+i \sin \theta)}=\color{royalblue}{3}\cdot\color{orangered}{(-1)}=\color{royalblue}{3}\cdot\color{orangered}{(\cos180+i \sin180)}$

7. zepdrix

Yes 180, good! :)

8. anonymous

so polar form is just 180degrees?

9. zepdrix

No, the polar form is everything on the right of that last equals sign. $\large\rm -3=3(\cos180^o+i \sin 180^o)$

10. anonymous

so that's my answer? 3 (cos180° +i sin180°) ?