Answer:
The third approximation is 
Step-by-step explanation:
We are given that


We have to find the second and third approximation of a root of given equation by using Newton's method.
We know that Newton's method , if nth approximation is given
and
then, the next approximation is given by


Substitute 


Substitute the value n=1 then, we get

Substitute the values then , we get the second approximation

For n=2




Hence, the third approximation is 