Posted by y912f on Friday, January 16, 2009 at 8:39pm.
a question just like this one was on one of my homeworks..i asked for help but i didn't understand the explanation..so i had to gues..nd now i have that kind of quesion again on my homework. pleease explain this thoroughly
find the value of s in the interval [0,pi/2] that makes the statement true
1. tan s= 6.86874202
thnks to whoever answers and explains it:)

trigonometry  Reiny, Friday, January 16, 2009 at 8:57pm
you are told that
tan s = + 6.86874..
so by the CAST rule, the angle must be in the I or III quadrant.
but our domain is from 0 to pi/2 which is only quadrants I and II.
and since they are using radians to describe the domain, we should also answer in radians.
set your calculator to radians,
enter
inv tan or 2nd function tan
6.68742..
=
I got s = 1.42622 radians 
trigonometry  y912f, Friday, January 16, 2009 at 9:02pm
ya see this somehow doesnt work on my calculator
[pi,3pi/2];tan s=1
so you have to enter inv tan 1??
confuusedd 
trigonometry  Reiny, Friday, January 16, 2009 at 9:20pm
let's try it with degrees first
set you calc to degrees
test #1
enter
tan
45
=
you should get 1
now work it backwards (the inverse)
at the top left you should have either an "INV" key or 2ndF key
enter:
2ndF
tan
1
=
you should get 45 degrees
If that doesn't work it could be that on your calc you have to enter the number first.
let me know if it worked.
If it worked, set your machine to radians and repeat the steps in the same way as noted above. 
trigonometry  y912f, Saturday, January 17, 2009 at 1:56pm
when i do tan 45 i get 1.6197..
do you know any site where i can use a calculator...  trigonometry  Damon, Saturday, January 17, 2009 at 2:12pm

trigonometry  y912f, Saturday, January 17, 2009 at 2:25pm
thnks:)

trigonometry  Reiny, Saturday, January 17, 2009 at 4:12pm
y912f, you have your calculator set to radians
yes, tan 45 radians = 1.6197
look for a key that says DRG, it will toggle your setting beteen degrees, radians and gradians 
trigonometry  y912f, Saturday, January 17, 2009 at 4:47pm
ya Damon already helped me understand the problem
i set it to radians. entered 1, atan and it equaled .785
then entered +, pi= 3.926radians
in other words 5pi/4
thanks for all your help tooo!!!!