Question 579845
{{{ 1/(x+1)! < .001  }}}
Multiply both sides by {{{ ( x + 1)! }}}
{{{ 1 < (1/1000)*( x + 1 )! }}}
Multiply both sides by {{{ 1000 }}}
{{{ ( x + 1 )! > 1000 }}}
{{{ x = 5 }}}
{{{ 6*5*4*3*2*1 = 720 }}}
{{{ x = 6 }}}
{{{ 7*6*5*4*3*2*1 = 5040 }}}
{{{ 5040 > 1000 }}}
{{{ x = 6 }}} is the answer