Answer:
the magnitude of the error is 2.9959 × 10⁻⁹
Step-by-step explanation:
By Alternating series estimation theorem
is satisfies
(i)
for all n
(ii) 
The formula for magnitude of error is

Let 
We can see 
For all n ∈ N
That means
for all n ∈ N


The alternating series estimation theorem is 
After stop adding the term with n = 6
the series tells that the error is smaller than the term with a
Therefore

the magnitude of the error is 2.9959 × 10⁻⁹