Hello ,

solve cosx = 2/7 for x [Pie , 2Pie]

My solution is first : Arc cos ==> 1.28 rd , 1.28/3.14 = 0.4076 Pie its not in the domain so what to do ? (Thinking) I don't know what to do after that ? please can you help me ?

Thanks

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- November 18th 2008, 07:50 AMiceman1Inverse trigonometric functions
Hello ,

solve cosx = 2/7 for x [Pie , 2Pie]

My solution is first : Arc cos ==> 1.28 rd , 1.28/3.14 = 0.4076 Pie its not in the domain so what to do ? (Thinking) I don't know what to do after that ? please can you help me ?

Thanks - November 18th 2008, 08:17 AMSoroban
Hello, iceman1!

By the way, it's not "pie" . . . it's "pi".

Quote:

Solve: .

My solution is first: . . ?? . Why?

**infinite**number of values.

. .

Now find so that the angle falls within the interval.

- November 18th 2008, 08:27 AMiceman1
oh thanks yeah sorry ''PI'' . 1.28/pi to get the result is PI ? coz its in Radian .

anway how to find n ? (Itwasntme) I need an exemple how to resolve this problem .

our teacher is drawing the circle and i m lost sometimes she adjust -Pi -x , +Pi + x (Worried) Please can you help me how to know ?

Thanks (Rock) - November 18th 2008, 11:22 AMHallsofIvy