Computer Forums sec(tan^-1(4/3))^2=25/9
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 12-13-2009, 09:06 PM #1 Golden Master     Join Date: Mar 2006 Posts: 5,574 sec(tan^-1(4/3))^2=25/9 Could someone explain why that is? __________________ __________________ AMD Athlon 64X2 4200+, 2 GB ram, 2 TB HDD, Ubuntu+SAMBA ♫ Lenovo T410, i5@ 2.4 GHz, 4 GB ram, 7
 12-13-2009, 09:30 PM #2 Golden Master     Join Date: Jul 2004 Location: USA Posts: 8,463 Re: sec(tan^-1(4/3))^2=25/9 Green __________________ __________________ When all else fails...Ham Radio! I still have the same old HP DV9700T laptop I've had for years...still kickin'
 12-13-2009, 10:14 PM #3 Site Team     Join Date: May 2006 Posts: 7,903 Re: sec(tan^-1(4/3))^2=25/9 You mean tan(4/3*pi)? hmm, nvm, 4/3pi doesnt get me that answer. I have no idea, I think that might be false. __________________ “Adults are just obsolete children and the hell with them.” - Dr. Suess
 12-13-2009, 10:48 PM #4 Guru     Join Date: Jan 2008 Location: U.S. Posts: 7,841 Re: sec(tan^-1(4/3))^2=25/9 It checks correctly. The inverse tangent of 4/3, denoted as tan^-1(4/3), is equal to approximately .9273 radians. This value is a little less than pi/3. Then, when you take the square of the secant of that value, denoted by (sec(.9237))^2, you get 25/9. What that statement says is the following: The square of the secant whose angle gives a slope of 4/3 is 25/9. Remember that secant is 1/cos. Make sure to type all of the parenthesis correctly in your calculator.
12-13-2009, 10:56 PM   #5
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Re: sec(tan^-1(4/3))^2=25/9

Quote:
 Originally Posted by JogaBonito1502 It checks correctly. The inverse tangent of 4/3, denoted as tan^-1(4/3), is equal to approximately .9273 radians. This value is a little less than pi/3. Then, when you take the square of the secant of that value, denoted by (sec(.9237))^2, you get 25/9. What that statement says is the following: The square of the secant whose angle gives a slope of 4/3 is 25/9. Remember that secant is 1/cos. Make sure to type all of the parenthesis correctly in your calculator.
I got the the problem by myself up until the "sec".
What is Secant?

Hm. Okay so it's hypotenuse over adjacent. Alrighty.
Haven't learned that yet I only have worked with sin, tan, and cos.
and of course also the inverse of all of those.
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12-13-2009, 11:16 PM   #6
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Join Date: May 2006
Posts: 7,903
Re: sec(tan^-1(4/3))^2=25/9

Quote:
 Originally Posted by JogaBonito1502 It checks correctly. The inverse tangent of 4/3, denoted as tan^-1(4/3), is equal to approximately .9273 radians. This value is a little less than pi/3. Then, when you take the square of the secant of that value, denoted by (sec(.9237))^2, you get 25/9. What that statement says is the following: The square of the secant whose angle gives a slope of 4/3 is 25/9. Remember that secant is 1/cos. Make sure to type all of the parenthesis correctly in your calculator.
tan(x)^-1 would be 1/tan(x) correct? And 1/tan(4/3) is not .9273....
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12-13-2009, 11:21 PM   #7
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Re: sec(tan^-1(4/3))^2=25/9

Quote:
 Originally Posted by superman22x tan(x)^-1 would be 1/tan(x) correct? And 1/tan(4/3) is not .9273....
You're mistaken.

1/tan(x) = cot(x); where x is an angle measurement
tan^-1(x) = y; where x is an number and y is an angle measurement such that tan (y) = x

 12-13-2009, 11:26 PM #8 Site Team     Join Date: May 2006 Posts: 7,903 Re: sec(tan^-1(4/3))^2=25/9 Oh, yeah, mixed up, lol. __________________ “Adults are just obsolete children and the hell with them.” - Dr. Suess
 12-14-2009, 12:36 AM #9 Golden Master     Join Date: Apr 2009 Location: USA Posts: 5,438 Re: sec(tan^-1(4/3))^2=25/9 ya, i sure as hell have no idea what your all talking about lol
 12-14-2009, 12:52 PM #10 Daemon Poster     Join Date: Mar 2005 Posts: 1,144 Re: sec(tan^-1(4/3))^2=25/9 Banned for Spam! P.S What am I looking at? __________________