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 ? I don't know what to do after that ? please can you help me ?
Thanks
Hello, iceman1!
By the way, it's not "pie" . . . it's "pi".
An inverse trig function has an infinite number of values.Solve: .$\displaystyle \cos x \:=\:\tfrac{2}{7}\quad\text{for }[\pi,\:2\pi]$
My solution is first: .$\displaystyle \arccos\left(\tfrac{2}{7}\right) \:=\:1.28\text{ rd} \quad\Rightarrow\quad \frac{1.28}{\pi}$ . ?? . Why?
. . $\displaystyle \arccos\left(\tfrac{2}{7}\right) \;=\;\pm1.281 + 2\pi n\;\;\text{ for any integer }n$
Now find $\displaystyle n$ so that the angle falls within the interval.
oh thanks yeah sorry ''PI'' . 1.28/pi to get the result is PI ? coz its in Radian .
anway how to find n ? 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 Please can you help me how to know ?
Thanks