November 1st, 2017, 11:17 AM  #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, 11:27 AM  #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, 11:47 AM  #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, 11:50 AM  #4 
Senior Member Joined: Aug 2012 Posts: 2,357 Thanks: 740  

Tags 
arctantan5pi or 8 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
tan and arctan issue  JohnofGaunt  Trigonometry  3  June 13th, 2014 10:10 PM 
Arctan function  Orlando895  Trigonometry  4  June 3rd, 2014 02:48 PM 
cos(arctan(4/3)arcsin(24/25)...  mared  Trigonometry  2  May 17th, 2014 11:45 AM 
arctan...  ungeheuer  Calculus  3  January 16th, 2013 04:17 AM 
arctan  danneman91  Algebra  2  October 3rd, 2011 12:11 PM 