Question

Problem 19

Answer 1

Given information

Given infinite series

 

Step-by-step explanation

Step 1.

Given series that  ,  since we know  

we know that is covergent  p-series with  

Compare from above series    is convergent.

 

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$\left| \frac{{{\cos }^{2}}n}{{{n}^{2}}+1} \right|\le \frac{1}{{{n}^{2}}}$