The equation is
and initial approximation is
.
Newtons approximation formula :
.
Consider
.
Apply derivative on each side with respect to
.


From the newtons method,
.
Substitutte
in above expression.

Substitutte
in above expression.


.
Consider
.
Substitutte
in above expression.
.
Substitutte
in above expression.

Third approximation to the root of the equation is
.
Third approximation to the root of the equation is
.