1.

`int(x^(2))/((x^(2)+4)(x^(2)+9))dx` का मान ज्ञात कीजिए ।

Answer» `int(x^(2))/((x^(2)+4)(x^(2)+9))dx`
माना `x^(2)=y` तथा आंशिक भिन्नों में व्यक्त करने पर ltbgt `(y)/((y+4)(y+9))=(A)/((y+4))+(B)/((y+9))" …(1)"`
`y=A(y+9)+B(y+4)`
यदि `" "y=-4," तब "A=-(4)/(5)`
और यदि `" "y=-9," तब "B=(9)/(5)`
अब समीकरण (1 ) से
`(y)/((y+4)(y+9))=(-4)/(5(y+4))+(9)/(5(y+9))`
`rArr" "(x^(2))/((x^(2)+4)(x^(2)+9))=(-4)/(5(x^(2)+4))+(9)/(5(x^(2)+9))`
`rArr int (x^(2))/((x^(2)+4)(x^(2)+9))dx=-(4)/(5)int(1)/((x^(2)+4))dx+(9)/(5)int(1)/((x^(2)+9))dx`
`=-(4)/(5)tan^(-1).(x)/(2).(1)/(2)+(9)/(5)tan^(-1).(x)/(3).(1)/(3)+c`
`=-(2)/(5)tan^(-1).(x)/(2)+(3)/(5)tan^(-1).(x)/(3)+c`


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