How do you solve $cos(pix)=0.5$ between the interval $0<=x<2$ ?

Question

4738 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-02-17T11:08:00

$color(blue)(x=1/3 ,5/3)$

$cos(pix)=0.5$

$pix=arccos(cos(pix))=arccos(0.5)=pi/3, (5pi)/3,(7pi)/3$ etc

$pix=pi/3=>x=pi/(pi3)=1/3$

$pix=(5pi)/3=>x=(5pi)/(pi3)=5/3$

$pix=(7pi)/3=>x=(7pi)/(pi3)=7/3$ ( too great )

$color(blue)(x=1/3 ,5/3)$

How do you solve cos(pix)=0.5cos(pix)=0.5 between the interval 0<=x<20<=x<2?