Using differentials, find approximate value of (0.009)^(1/3)(0.009)13?

1 Answer
Nov 28, 2017

0.020830.02083 (real value 0.02080080.0208008)

Explanation:

This can be solved with the formula of Taylor:

f(a+x)=f(a)+xf'(a)+(x^2/2)f''(a)....

If f(a)=a^(1/3)

We will have:

f'(a)=(1/3)a^(-2/3)

now if a=0.008 then

f(a)=0.2 and

f'(a)=(1/3)0.008^(-2/3)=25/3

So if x=0.001 then

f(0.009)=f(0.008+0.001)~~f(0.008)+0.001xxf'(0.008)=

=0.2+0.001*25/3=0.2083