3-i in trigonometric form

May 2010
4
0
3-i

my main problem is finding the angle, the book's full answer is square root of 10 cis 5.96 (radians) how do i get 5.96 radians?

im supposed to use arctan(y/x) but im getting it wrong.
 

pickslides

MHF Helper
Sep 2008
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1,625
Melbourne
What is the question?
 
May 2010
4
0
i think i get in now, if you do arctan(-1/3) you get -18.4, so you add 360 to -18.4 and then you get 341.6 degrees which is 5.96 radians.

Quick question, is it okay to leave the argument as degrees or does it have to be in radians?
 

pickslides

MHF Helper
Sep 2008
5,237
1,625
Melbourne
Quick question, is it okay to leave the argument as degrees or does it have to be in radians?
Either is fine, radians is preffered in most walks of life.

Sometimes the question itself will say what is required.