Question 1183233


{{{7cos(4x)=5}}} for the smallest three positive solutions.

{{{cos(4x)=5/7 }}}

{{{4x=cos^-1(5/7 )}}}

{{{x=cos^-1(5/7 )/4}}}

in general:

{{{x=cos^-1(5/7 )/4+(pi/2)*n}}}

{{{x=pi/2-cos^-1(5/7 )/4+(pi/2)*n}}}


three smallest exact solutions:

{{{x= cos^-1(5/7 )/4+(pi/2)*0}}}=>{{{x=cos^-1(5/7 )/4}}}
{{{x=cos^-1(5/7 )/4+(pi/2)*1}}}=>{{{x=cos^-1(5/7 )/4+pi/2}}}
{{{x=pi/2-cos^-1(5/7 )/4+(pi/2)*0}}}=>{{{x=pi/2-cos^-1(5/7 )/4 }}}


approximate solutions in decimal form:

{{{x=0.1937975}}}
{{{x=1.3769988267948965}}}
{{{x=1.7645938267948966}}}