InterviewSolution
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सिद्ध कीजिए कि - `int(1)/(x[6(logx)^(2)+7 logx+2])dx=log|(1+logx^(2))/(2+logx^(3))|+c` |
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Answer» माना `logx=t` `rArr" "(1)/(x)dx=dt` माना `" "I=int(1)/(x[6(logx)^(2)+7logx+2])dx` `" "=int(1)/(6t^(2)+7t+2)dx` `" "=int(1)/(6t^(2)+7t+2)dx` `" "=int(1)/((3t+2)(2t+1))dt` पुनः माना `(1)/((3t+2)(2t+1))=(A)/(3t+2)+(B)/(2t+1)=(A(2t+1)+B(3t+2))/((3t+2)(2t+1))` `rArr" "A(2t+1)+B(3t+2)=1` समान घातों के गुणांकों को बराबर रखने पर `2A+3B=0` `A+2B=1` हल करने पर `B=2, A=-3` `therefore(1)/((3t+2)(2t+1))=(-3)/(3t+2)+(2)/(2t+1)` और `I=int(-3)/(3t+2)dt+int(2)/(2t+1)dt` `=-log|3t+2|+log|2t+1|+c` `=log|(2t+1)/(3t+2)|+c=log|(1+2logx)/(2+3logx)|+c` `=log|(1+logx^(2))/(2+logx^(3))|+c` |
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