Find the integrating factor μ(x)\displaystyle \mu{\left({x}\right)}  of

     y+7ycos(x)=0\displaystyle {y}'+{7}{y}-{\cos{{\left({x}\right)}}}={0}

such that μ(0)=1\displaystyle \mu{\left({0}\right)}={1}

 μ(x)=\displaystyle \mu{\left({x}\right)}=