Question 947785

{{{4cos(theta) = 1}}}

{{{cos(theta) = 1/4}}}

{{{theta = 2 pi*n-cos^(-1)(1/4)}}},   {{{n}}} element {{{Z}}}

first find
{{{cos^(-1)(1/4) =75.52}}}° or {{{1.31811607}}} radians

that is
{{{theta = 2 pi*n-cos^(-1)(1/4)}}}, if  {{{n =0}}}

{{{theta = 2 pi*0-cos^(-1)(1/4)}}}
{{{theta =1.31811607}}} radians
{{{theta =75.52}}}°

second angle

{{{theta = 2pi*1-cos^(-1)(1/4)}}},  if {{{n =1}}}

{{{theta = 2pi-1.31811607}}}
{{{theta = 6.2831853-1.31811607}}}
{{{theta =  4.96506923}}}
{{{theta =284.295008}}}°