1.

सिद्ध कीजिएः की `int_(0)^(1) tan^(-1)xdx=pi/4-1/2log2.`

Answer» माना `I=underset(0)overset(1)int tan^(-1)xdx " "x=tan theta ` रखने पर
`dx=sec^(2) theta d theta`
जब x=0 तब `theta=0` तथा
जब x=1 तब `theta=pi/4`
`therefore I=underset(0)overset(pi/4)int tan^(-1)(tan theta) sec^(2) theta d theta `
`=underset(0) overset(pi/4)int theta sec^(2) d theta`
`=[theta int theta sec^(2) d theta]_(0)^(pi)-underset(0)overset(pi/4)int {(d)/(d theta) intsec^(2) theta d theta}d theta`
`=[theta tan theta]_(0)^(pi//4)-underset(0)overset(pi//4)int tan theta d theta`
`=[pi/4tan""pi/4-0]+[log cos theta]_(0)^(pi//4)`
`=pi/4. 1 log cos""pi/4-log cos theta`
`=pi/4-log ""1/sqrt2-log 0`
`[therefore log 1=0" तथा "pi/4log ""1/A=-logA]`
`therefore I=pi/4-1/2log2 `


Discussion

No Comment Found