Question 929091
This is the difference of two squares.
{{{100cos^2(x)-25=0}}}
{{{(10cos(x)-5)(10cos(x)+5)=0}}}
Two solutions:
{{{10cos(x)-5=0}}}
{{{10cos(x)=5}}}
{{{cos(x)=1/2}}}
{{{x=pi/3}}} and {{{x=(5/3)pi}}}
and
{{{10cos(x)+5=0}}}
{{{10cos(x)=-5}}}
{{{cos(x)=-1/2}}}
{{{x=(2/3)pi}}} and {{{x=(4/3)pi}}}