Question 1087689
a)  {{{ Area = pi*r^2 }}} so {{{ 900pi = pi*r^2 }}} —> {{{ 900 = r^2 }}} —> {{{ highlight(r = 30cm) }}}

b)  For a tolerance of +/- {{{ 10cm^2 }}}, the Area A can fall in this range: (approx) {{{ 896.8(pi)cm^2 <= A <= 903.2(pi)cm^2}}} so the radius can vary over the range {{{ sqrt(896.2) <= r <= sqrt(903.2) }}}cm
or approx. {{{ 29.937 <= r <= 30.053 }}} cm so that means the radius can vary approx.  {{{ -0.063 <= v <= 0.053 }}} cm from the ideal (v = variation from ideal).

c)  
<pre>
           x is the independent variable, I'd say it corresponds to 'r' in the above.
         f(x) is a function of x,  and it corresponds to Area in the above.
           a  is a constant that x approaches, (30cm)
           L  is the limit,   ( {{{ 900(pi)cm^2 }}} )
          The limit is defined such that for 0<|x-p|<{{{delta}}},   |f(x) - L| < {{{ epsilon }}}  for real {{{epsilon>0}}} and real {{{ delta > 0}}}.   My guess is {{{ 0 < delta <= 0.053cm }}} and {{{ 0<epsilon<=10cm^2 }}}  

 </pre>          

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