Question 1205932


{{{ 4cos^2( x )- 3 = 0}}} for all {{{x}}}

{{{4cos^2( x )= 3}}}

{{{cos^2( x )= 3/4}}}

{{{cos( x )= sqrt(3/4)}}}

{{{cos( x )= sqrt(3)/2 }}} or {{{cos( x )= -sqrt(3)/2}}}


Solutions

{{{x = cos^-1( sqrt(3)/2)}}}

{{{x = pi/6}}}

general: {{{x = pi*n - pi/6}}}, {{{n}}} element {{{Z}}}

or

{{{x = cos^-1( -sqrt(3)/2)}}}

{{{x = 5pi/6}}}

general:{{{ x = pi*n - 5pi/6}}}, {{{n }}}element {{{Z}}}