November 1st, 2017, 12:17 PM  #1 
Newbie Joined: Oct 2017 From: Redlands, CA Posts: 15 Thanks: 0  arctan(tan(5pi/8))
arctan(tan(5pi/8 )) I got lost on this problem on an exam. I know by putting in a calculator that the solution is 3pi/8 but I had to show work. Could you guys explain the approach? 
November 1st, 2017, 12:27 PM  #2 
Newbie Joined: Oct 2017 From: Redlands, CA Posts: 15 Thanks: 0 
I know arctan means inverse. I’m just looking for direction on how you would show the work to solve for an exact solution.

November 1st, 2017, 12:47 PM  #3 
Newbie Joined: Oct 2017 From: Redlands, CA Posts: 15 Thanks: 0 
Oh I get it now. It would be 5pi/8 because the arctan would cancel the tan but arctan is restricted to (pi/2, pi/2) and since 5pi/8 is greater than pi/2 you find the equivalent angle within the restriction which is 3pi/8. Is this correct?

November 1st, 2017, 12:50 PM  #4 
Senior Member Joined: Aug 2012 Posts: 1,638 Thanks: 415  

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