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Express-1-5-9-in-partial-fraction-




Question Number 151426 by peter frank last updated on 21/Aug/21
Express (1/(5×9)) in partial fraction
Express15×9inpartialfraction
Answered by liberty last updated on 21/Aug/21
 (1/(n(n+4)))=(a/n)+(b/(n+4))   a= [(1/(n+4)) ]_(n=0) =(1/4)  b= [(1/n) ]_(n=−4) =−(1/4)   (1/(n(n+4)))=(1/(4n))−(1/(4(n+4)))  n=5⇒(1/(5×9)) =(1/(20))−(1/(36))
1n(n+4)=an+bn+4a=[1n+4]n=0=14b=[1n]n=4=141n(n+4)=14n14(n+4)n=515×9=120136
Answered by MJS_new last updated on 21/Aug/21
it′s not unique  (1/((a−b)(a+b)))=(1/(2(a−b)b))−(1/(2(a+b)b))=       [a=7∧b=2]  =(1/(20))−(1/(36))  but  (1/((a−b)(a+b)))=(1/(2a(a+b)))+(1/(2a(a−b)))=       [a=7∧b=2]  =(1/(126))+(1/(70))
itsnotunique1(ab)(a+b)=12(ab)b12(a+b)b=[a=7b=2]=120136but1(ab)(a+b)=12a(a+b)+12a(ab)=[a=7b=2]=1126+170
Answered by MJS_new last updated on 21/Aug/21
(1/(5×9))=(1/a)+(1/b) with a≥b   ((a),(b) ) ∈{ (((18)),((−30)) ) ,  (((20)),((−36)) ) ,  (((30)),((−90)) ) ,  (((36)),((−180)) ) ,  (((40)),((−360)) ) ,  (((42)),((−630)) ) ,  (((44)),((−1980)) ) ,  (((90)),((90)) ) ,  (((120)),((72)) ) ,  (((126)),((70)) ) ,  (((180)),((60)) ) ,  (((270)),((54)) ) ,  (((450)),((50)) ) ,  (((720)),((48)) ) ,  (((2070)),((46)) ) }
15×9=1a+1bwithab(ab){(1830),(2036),(3090),(36180),(40360),(42630),(441980),(9090),(12072),(12670),(18060),(27054),(45050),(72048),(207046)}

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