${\displaystyle \underset{n=1}{\overset{}{}}}(-1{)}^n\frac{x^n}{(2^n+1)(n^2+1)}$ serisinin $R$ yak$$nsakl$$k yar$$ap$$ i$$in a$$a$$dakilerden hangisi do$$rudur$?$

a$)-\frac{1}{\sqrt[\phantom{2}]{3}}R<mfrac><mrow><mn>1</mn></mrow><mrow><mroot><mrow><mn>3</mn><mspace\; width="thinmathspace"></mspace></mrow><mrow><mphantom><mn>2</mn></mphantom></mrow></mroot></mrow></mfrac>$

b$)-\frac{1}{3}R<mfrac><mrow><mn>1</mn></mrow><mrow><mn>3</mn></mrow></mfrac>$

c$)\frac{3}{2}R\frac{5}{2}$

d$)-\sqrt[\phantom{2}]{3}R\sqrt[\phantom{2}]{3}-1$

$e$