\(\eqalign{
& \Delta f\left( 1 \right) = \Delta x + 3{\left( {\Delta x} \right)^2} + {\left( {\Delta x} \right)^3}, \cr
& \Delta f\left( 1 \right) = \Delta x. \cr} \)
a) \(\Delta f\left( 1 \right) = 5 > df\left( 1 \right) = 1.\)
b) \(\Delta f\left( 1 \right) = 0,131 > df\left( 1 \right) = 0,1.\)
c) \(\Delta f\left( 1 \right) = 0,010301 > df\left( 1 \right) = 0,01.\)