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 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
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 Originally Posted by JPow 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?
Yes.

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