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¶¨»ý·ÖÌâÄ¿²»»á×öº¯Êýf(x)=¡Ò lnt dtµÄ¼«ÖµµãÊÇ - - - ?»ý·Ö...

ËùÒÔ¼«Ð¡µãΪf(1) = ¡Ò(1/2~1) lnt dt = [tlnt - t] |(1/2~1)= (-1) - [(1/2)(-ln2) - 1/2]= (ln2 - 1)/2 º¯Êýf(x)=¡Ò(1/2~x)...


ln(1+x)µÄ»ý·ÖÔõôËã°¡?

¡Òln(1+x)dx = ¡Òln(1+x)d(1+x) = ¡Òlntdt = tlnt - ¡Òtd(lnt) = tlnt - ¡Òdt = tlnt - t + C = (1+x)ln(1+x) - x + C


¶¨»ý·Ö¡Òlnsinxlncosxsin2xdxÓ¦¸ÃÔõô½â?

x\cos x]dx\\ &=\frac{1}{2}(2\int_{0}^{1}\frac{(1-t^2)}{t}\ln\sqrt{1-t^2}dt-\frac{1}{2}\int_{0}^{1}\ln...


ÈçºÎ»ý 1/ln(x)?

ÈçºÎ»ý 1/ln(x)£¿Å·À­Ò²Ë¼¿¼¹ýÕâ¸öÎÊÌâ, ×îºóËû·¢ÏÖÕâ¸öÎÞ·¨ÓóõµÈº¯Êý±í´ï, ÓÚÊÇËû¹æ¶¨¡Ò2x1log(t)dt=Li(x), ÏÖ´úµÄÖ¤Ã÷ÔòÒ»°ã²ÉÓÃ...


¼ÆËã²»¶¨»ý·Ö

Áît=x+1,dt=dx ԭʽ=¡Òlnt dt =tlnt-¡Òdt,·Ö²¿»ý·Ö·¨ =tlnt-t+C =(x+1)ln(x+1)-x-1+C =(x+1)ln(x+1)-x+C1,³£Êý C1=C-1 ÏêÇé...


¡Ò(0 - 1)lntd(tµÄn +1´Î)Ôõô»¯¼ò

d(t^ n+1)=lnt *t^(n+1) -¡Ò t^n+1 d(lnt)=lnt *t^(n+1) -¡Ò t^n dt =lnt *t^(n+1) -1/(n+1) *t^(n+1)´Ëʱ´úÈët µÄÉÏÏÂÏÞ¼´¿É ...


(¢ñ)±È½Ï¡Ò10|lnt|[ln(1+t)]ndtÓë¡Ò10t2|lnt|dt(n=1,2...

(1)¹¹Ô캯Êýf(t)=ln(1+t)-t¶Ôº¯Êýf(t)Ç󵼵õ½:f¡ä(t)=11+t 1= t1+t¡àµ±t>0ʱ,ÓÐ f¡ä(t)<0¡àf(t)<f(0)=0¡à0<ln(1+t)<t¡à0<[ln(1+t)]...


Éèf(x)=¶¨»ý·Ö(ln(1+t)/t)dt(x>0),ÉÏÏÞx,ÏÂÏÞ1,Çóf(x...

Éè f(x)=¡Ò[1,x] ln(1+t)/t dt Áîu=1/t=¡Ò[1,1/x] uln(1+1/u) d1/u =¡Ò[1,1/x] -[ln(1+u)-lnu] / udu=¡Ò[1,1/x] -ln(1+u) / ...


¡Ò[0, 1] ln¦£(x)dx ÔõôÇó°¡?

\sin\pi x)dx}_{\color{blue}{·ÖÀë}} \\ &=\underbrace{\frac{1}{2}\ln\pi-\frac{1}{2\pi}\int_0^\pi \ln(\sin t)dt}...


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