Question 1170388


{{{sin(2x)-cos(x)=0}}}

rewrite using trig identities  {{{sin(2x)=2sin(x)cos(x)}}}

{{{2sin(x)cos(x)-cos(x)=0}}}

{{{(2sin(x) -1)cos(x)=0}}}

solutions:

{{{2sin(x) -1=0}}} ->{{{sin(x)=1/2}}}
or
{{{cos(x)=0}}}


if {{{sin(x)=1/2}}} then {{{sin^-1(1/2)=30}}}°
if {{{cos(x)=0}}} then {{{cos^-1(0)=90}}}°

answer: b. {{{90}}} degrees