MathLabs

Problem 2

Let a1,a2,a3,a4,a5a_1,a_2,a_3,a_4,a_5 be real numbers satisfying a1k2+1+a2k2+2+a3k2+3+a4k2+4+a5k2+5=1k2\frac{a_1}{k^2+1}+\frac{a_2}{k^2+2}+\frac{a_3}{k^2+3}+\frac{a_4}{k^2+4}+\frac{a_5}{k^2+5}=\frac1{k^2} for k=1,2,3,4,5k=1,2,3,4,5. Find the value of a137+a238+a339+a440+a541\frac{a_1}{37}+\frac{a_2}{38}+\frac{a_3}{39}+\frac{a_4}{40}+\frac{a_5}{41} (express the value in a single fraction).
Step 5 of 5: Evaluate at 6
1−36R(6)=−231374699⟹R(6)=18746567445821-36R(6)=-\frac{231}{374699}\Longrightarrow R(6)=\frac{187465}{6744582}
Detailed analysis

Substitute x=6. The numerator product is 35·32·27·20·11 and the denominator product is 37·38·39·40·41, so 1−36R(6)=−231/374699. Solving gives the required value R(6)=187465/6744582.