calculate-n-0-1-n-2-1-and-n-0-1-n-n-2-1- Tinku Tara June 3, 2023 Relation and Functions 0 Comments FacebookTweetPin Question Number 67559 by Abdo msup. last updated on 28/Aug/19 calculate∑n=0∞1n2+1and∑n=0∞(−1)nn2+1 Commented by ~ À ® @ 237 ~ last updated on 28/Aug/19 letnamedf(a)=∑∞n=01n2+a2andg(a)=∑∞n=0(−1)nn2+a2f(a)=12∑∞−∞1n2+a2=−12[Res(A(z),ia)+Res(A(z),−ia)]withA(z)=πcot(πz)z2+1(thatformulacomesfromtheResidutheorem…Res(A(z),ia)=πcot(iπa)2ia=−πcoth(πa)2acausetanx=−ith(ix)⇒cot(x)=icoth(ix)Res(A(z),−ia)=πcot(−iπa)−2ia=−πcoth(πa)2aSof(a)=π2acoth(πa)g(a)=12∑∞−∞(−1)nn2+a2=−12[Res(B,ia)+Res(B,−ia)]withB(z)=πcsc(πz)z2+1=π(z2+1)sin(πz)Res(B,ia)=π2iasin(iπa)=π2ia(e−πa−eπa2i)=π−2ash(πa)Res(B,−ia)=π−2iasin(−iπa)=π−2ash(πa)Sog(a)=π2ash(πa) Commented by mathmax by abdo last updated on 28/Aug/19 thankyousir. Commented by mathmax by abdo last updated on 29/Aug/19 wehaveprovedtbate−∣x∣=1−e−ππ+2π∑n=1∞(1−(−1)ne−π)1+n2cos(nx)(developpementatfourierserie)x=0⇒1=1−e−ππ+2π∑n=1∞1n2+1−2πe−π∑n=1∞(−1)nn2+1⇒π=1−e−π+2∑n=1∞1n2+1−2e−π∑n=1∞(−1)nn2+1x=π⇒e−π=1−e−ππ+2π∑n=1∞(1−(−1)ne−π)n2+1(−1)n⇒e−π=1−e−ππ+2π∑n=1∞(−1)nn2+1−2π∑n=1∞e−πn2+1⇒πe−π=1−e−π+2∑n=1∞(−1)nn2+1−2e−π∑n=1∞1n2+1letx=∑n=1∞1n2+1andy=∑n=1∞(−1)nn2+1wegetπ=1−e−π+2x−2e−πyandπe−π=1−e−π+2y−2e−πx⇒{2x−2e−πy=π−1+e−π−2e−πx+2y=πe−π−1+e−πΔ=|2−2e−π−2e−π2|=4−4e−2π≠0⇒Δx=|π−1+e−π−2e−ππe−π−1+e−π2|=2π−2+2e−π+2e−π(πe−π−1+e−π)=2π−2+2e−π+2πe−2π−2e−π+2e−2π=2π−2+4πe−2πΔy=|2π−1+e−π−2e−ππe−π−1+e−π|=2πe−π−2+2e−π+2e−π(π−1+e−π)=2πe−π−2+2e−π+2πe−π−2e−π+2e−2π=4πe−π−2+2e−2π⇒x=ΔxΔ=2π−2+4πe−2π4−4e−2π=π−1+2πe−2π2−2e−2π=∑n=1∞1n2+1y=ΔyΔ=4πe−π−2+2e−2π4−4e−2π=2πe−π−1+e−2π2−2e−2π=∑n=1∞(−1)nn2+1∑n=0∞1n2+1=1+x=1+π−1+2πe−2π2−2e−2π∑n=0∞(−1)nn2+1=1+y=1+2πe−π−1+e−2π2−2e−2π Terms of Service Privacy Policy Contact: info@tinkutara.com FacebookTweetPin Post navigation Previous Previous post: Question-133094Next Next post: Assuming-that-word-population-is-6-billion-and-total-world-trips-is-4-8-billion-a-what-is-the-country-potential-generation-index-CPG-I-of-the-country-b-interprete-your-results-in-a-above- Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Save my name, email, and website in this browser for the next time I comment.