Question 307483
{{{ (1) / (1 + (1/(x+1)))  }}}
= {{{ (1) / ((x+2)/(x+1)))  }}}
= (x+1)/(x+2)
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f(x) = {{{(x+1)*(x+2)^-1 }}}
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f'(x) = {{{ (x+2)^-1 + -1(x+1)(x+2)-2}}}
= {{{ (x+2)/(x+2)^2 - (x+1)/(x+2)^2}}}
= {{{1/(x+2)^2}}}